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# Summary of Public Comments and Responses for Aerospace Manufacturing and Rework Facilities Risk and Technology ReviewOctober 2015



## Summary of Public Comments and Responses for Aerospace Manufacturing and Rework Facilities Risk

and Technology Review

U. S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policies and Programs Division (D243-02) Research Triangle Park, North Carolina 27711iii

The primary contact regarding questions or comments on this document is:

Kim Teal (919) 541-5580

U.S. Environmental Protection Agency

OAQPS/Sector Policies and Programs Division (D243-02)

Research Triangle Park, North Carolina 27711

Email: Teal.Kim@epa.goviv 

### TABLE OF CONTENTS

Page

1.0 Introduction ........................................

................................................... ........................1

2.0 List of Commenters ..................................

................................................... ..................2

3.0 General Support ....................................

................................................... .....................3

4.0 Modeling Data Files ..................................

................................................... ..................3

5.0 Risk Modeling and Determination ........................

................................................... .....3

6.0 Technology Review ......................................

................................................... ............. 35

7.0 Proposed Regulation of Specialty Coatings .................... ............................................ 40

7.1 Legal Basis to Regulate Specialty Coatings ............. ........................................... 40

7.2 Determination of Specialty Coating Limits and Definitions ................................ 45

7.3 Specialty Coating Application Equipment Requirements ... ................................. 53

7.4 Specialty Coating Inorganic HAP Control Requirements ... ................................. 56

7.5 Specialty Coating Compliance Deadline.................. ........................................... 61

7.6 Complying with the Proposed Specialty Coating Limits .... ................................. 62

8.0 Startup, Shutdown, Malfunction Provisions ................ .............................................. 68

9.0 Electronic Reporting Provisions ........................

................................................... ...... 72

10.0 Alternative Compliance Demonstration ..................... ................................................ 73

11.0 Other Emission Sources Not Currently Regulated .......... .......................................... 77

12.0 Estimated Cost, Economic, and Environmental Impacts ....... .................................... 79

13.0 Technical Corrections................................

................................................... ............... 87

14.0 Comments Outside the Scope of the Proposal ............. ............................................... 89v



### List of Acronyms and Abbreviations

AEGL Acute Exposure Guideline Levels ASTM American Society of Testing and Materials ATSDR Agency for Toxic Substances and Disease Registry BACT Best Available Control Technology

CAA Clean Air Act CFR Code of Federal Register DoD U.S. Department of Defense

EA Environmental Assessment

EJ Environmental Justice EMP Environmental Monitoring Program

EO Executive Order EPA U. S. Environmental Protection Agency ERPG Emergency Response Planning Guidelines ERT Electronic Reporting Tool FR Federal Register GACT generally available control technologies GHG greenhouse gas x 1

HAP Hazardous Air Pollutant HEM-3 Human Exposure Model, version 3 HON Hazardous Organic NESHAP HQ Head Quarters ICR Information Collection Request IRIS Integrated Risk Information System

LAER Lowest Achievable Emission Rate MACT Maximum Achievable Control Technology

MIR Maximum Individual Risk μg/dL micrograms per deciliter NAAQS national ambient air quality standard NAS National Academy of Sciences NEI National Emissions Inventory

NESHAP National Emission Standards for Hazardous Air P ollutants

NRC National Research Council

NSPS New Source Performance Standards OAQPS Office of Air Quality Planning and Standards OMB Office of Management and Budget PM particulate matter POM Polycyclic Organic Matter PRA Paperwork Reduction Act RACT Reasonably Available Control Technology RBLC RACT/BACT/LAER Clearinghouse RCRA Resource Conservation and Recovery Act REL CalEPA Reference Exposure Level

RfC Reference Concentration

RfD Reference Dosevi

RTR Residual Risk and Technology Review SAB Science Advisory Board

SBA Small Business Administration SSM startup, shutdown, and malfunction TOSHI Target Organ-Specific Hazard Index
tpy tons per year USGS U.S. Geological Survey VOC volatile organic compound XML eXtensible Markup Language1



### 1.0 Introduction

On February 17, 2015, the Environmental Protection Agency (EPA ) proposed revisions to the

National Emission Standards for Hazardous Air Pollutants (NESHAP) for the Aerospace Manufacturing and Rework Facilities source category. Som e significant comments and responses appear in the preamble to the final rule. This document co ntains summaries of all the public comments that the EPA received on the proposed standards (comments that are summarized and addressed in the preamble to the proposed rule are also summa rized in this document for completeness). Copies of all comments submitted are ava ilable at the EPA docket Center Public Reading Room. Comment letters are also available electr onically through http://www.regulations.gov by searching Docket ID No. EPA-HQ -OAR-2014-0830.2



### 2.0 List of Commenters

The EPA received 14 comment letters after February 17, 2015 o n the proposed revisions to the NESHAP for the aerospace manufacturing and rework sourc e category. All comment letters are contained in Docket EPA-HQ-OAR-2014-0830. The commenter, affi liation, and item number in Docket EPA-HQ-OAR-2014-0830 are listed in Table 2-1.

Table 2-1. Public Comments Received after the Proposed Rule for Aerospace Manufacturing and Rework Facilities Risk and technology Review, Proposed Rule Docket EPA-HQ-OAR-2014-0830

Commenter Identification Code Commenter and Affiliation
EPA-HQ-OAR-2014-0830-0021 Anonymous public comment
EPA-HQ-OAR-2014-0830-0022 John D. Conway, EHS Compliance Manage r, Sikorsky Aircraft Corporation
EPA-HQ-OAR-2014-0830-0023 Thelma Latimer-Davis, Manager Environmenta l Engineering, American Airlines, Inc.

EPA-HQ-OAR-2014-0830-0024 (duplicate of 0022) John D. Conway, EHS Compliance Manager, Sikorsky Aircraft Corporation
EPA-HQ-OAR-2014-0830-0025 Donald R. Schregardus, Deputy Assistant Sec retary of the Navy, Department of the Navy, U.S. Department of

Defense
EPA-HQ-OAR-2014-0830-0026 Nancy N. Young, Esq., Vice President, En vironmental Affairs, Airlines for America
EPA-HQ-OAR-2014-0830-0027 David Darling, P.E., Senior Director, Enviro nmental Affairs; Timothy Serie, Esq., Counsel, Government Affairs, American Coatings Association

EPA-HQ-OAR-2014-0830-0028 

### Leslie Riegle, Director of Environmental Policy, Aerospace

Industries Association
EPA-HQ-OAR-2014-0830-0029 LMS Technologies, Inc.

EPA-HQ-OAR-2014-0830-0030 Earth Justice, on behalf of California C ommunities Against Toxics and Sierra Club
EPA-HQ-OAR-2014-0830-0031 G. Vinson Hellwig, Michigan, and Robert H . Colby Chattanooga, Tennessee, Co-Chairs, Air Toxics Committee, National Association of Clean Air Agenci es EPA-HQ-OAR-2014-0830-0032 (duplicate of 0028) 

### Leslie Riegle, Director of Environmental Policy, Aerospace

Industries Association3



### 3.0 General Support

Comment: One commenter s0830-0021) supported the proposed rule. The comme nter argued that hazardous air pollutants (HAP) are very harmful to the global population's health because

certain HAP can cause cancer or other serious health effects such as reproductive defects or birth defects, or have adverse effects on the environment.

Response: The EPA acknowledges the commenter's support.



### 4.0 Modeling Data Files

Comment: One commenter (0830-0022) submitted two corrections for their facility. The first was to apply an assumed scrubber efficiency of 95 percent for control of sodium dichromate on a metal finishing tank, and the second was a refined estimate of the chromium trioxide emissions from a stack serving chromic acid strip and pickle tanks with the emissions being for the two tanks combined instead of separately for each tank.

Response: The EPA acknowledges the commenter's corrections. The se were the only corrections received during the public comment period, and they both lowe red the estimated emissions from this facility. Because the residual risk analysis perform ed before proposal already found that the risks were acceptable with an ample margin of safety, the EPA did not repeat the analyses using

these new data.



### 5.0 Risk Modeling and Determination

Comment: One commenter (0830-0028) confirmed, after having risk modeling ex perts run EPA's risk model using EPA data, that EPA's conclusion that risks are approximately an order of magnitude below the level considered acceptable under CAA s ection 112 and EPA regulations. The commenter also argued that they determined that EPA l ikely overstated risks due to the conservative nature of risk modeling, including mis-located so urces, suspect emission outliers, and non-representative receptors.

The commenter also stated that EPA’s risk estimates m ay overstate the risk at the highest-risk facilities because of suspect data issues in the risk c alculations. Based on their review of the ten facilities that EPA calculated as having the highest fac ility-wide cancer risk, the commenter identified data and methodological issues (e.g., mis-loca ted sources, emission outliers, and nonrepresentative risk receptors) that would affect the cal culated risk numbers at five of the ten

facilities. The commenter noted that correction of these issues would likely result in substantially lower risk at several of the facilities, and in no ca ses would corrections result in higher modeled

risk. The commenter concluded that the issues identifie d at the highest-risk sources uniformly bias the modeling results to overstate the risk.

The commenter stated that EPA’s modeled hazard quotient (H Q) value of 2 at one facility is likely the result of errors in the modeling or input data for this facility. The commenter argued that EPA should have compared the California EPA 6-hour be nchmark for ethylene glycol ethyl ether acetate (EGEEA) to the calculated maximum 6-hour average emission concentration for this facility instead of to the calculated maximum 1-hour average emission concentration for the4

facility, stating that this correction alone would reduc e the HQ to approximately 1. The

commenter further noted that the EGEEA emissions for this facility are likely significantly

overstated because the stated emissions are more than 10 times the EGEEA emissions of much larger facilities, and correcting the facility’s emiss ions to reflect the industry average would reduce the HQ value to well below 1.

If EPA assumed significantly higher hourly emissions (a s much as 5 times higher), the highest estimated acute risk level, including corrected errors, wo uld still remain below an HQ value of 2. Therefore, the commenter agreed with EPA’s finding that acute risk from this source category is acceptable, even when using the modeled HQ of 2.

Response: The commenter suggested that the EPA has over estimated risks as a result of data and/or modeling errors. As noted in the risk report, the m odel inputs for risk modeling were derived from 2011 survey data from an information collectio n request (ICR) as well as emission data updated in 2013 and 2014. The more recent and/or corrected dat a that the commenter

references was not available at the time that the ri sk modeling was performed. EPA disagrees that methodological issues are present in the risk mode ling. Receptors around each facility are based on USGS census block locations and are adjusted in c ases where a census block is identified on property. As exact property lines are not pro vided as part of the ICR data set EPA conservatively leaves questionable receptors in the modeling analysis, and it is only in a situation where a facility shows the potential to pose a signifi cant risk that EPA may further explore whether a resident is located at that particular loca tion.

EPA disagrees that the acute value for EGEAA was in er ror. As noted above, inputs were based

on the ICR data available at the time of the assessme nt. Further, EPA compares 1-hour acute concentrations from the dispersion model with the Cali fornia Reference Exposure Levels (RELs) as a first-level acute screening value. As noted, EPA agre es that the HQ value of 2 is not expected to result in any negative health impacts.

Comment: One commenter (0830-0028) argued that while the risk from MAC T-allowable emissions is low and that risks are acceptable, this ri sk factor is not required for such a finding as evidenced in both the Coke Oven NESHAP [70 Fed. Reg. 19992, 19998 (Apr il 15, 2005)] and the Hazardous Organic NESHAP (HON) [71 Fed. Reg. 76603, 76609 (Decemb er 21, 2006)]. In regards to these two rules [70 Fed. Reg. 19998-99; 71 Fed. Reg. 34422, 34428-29] i n which EPA

stated that the use of MACT-allowable emissions was rea sonable, the commenter pointed out

that EPA chose to use actual emissions to determine risk because those were the most accurate

data available.

The commenter stated that the use of actual emissions in risk assessments is more accurate than MACT-allowable emissions and is supported by the language of CAA Section 112(f) because

the statute limits the risk review to consider risks t o the individual most exposed to the emissions from a particular source and does not include words such as “maximum allowable” or “potential.” The commenter further noted that not using MA CT-allowable emissions is reasonable as they represent a hypothetical, worst-case emissions level to which an individual is unlikely to ever be exposed, plus (similar to the HON [71 F ed. Reg. at 76610]) there is no reason to conclude that sources in this source category could make changes that significantly increase their emissions and risks while still complying with MAC T requirements. The commenter stated5

that actual emissions are the most reasonable to use in risk approximation for this source category because aerospace manufacturers are constrai ned in terms of the ability to change the coatings and materials used, face relatively stable mar ket conditions, and have limited excess capacity. The commenter also noted that basing the emiss ion standard on unlikely, worst-case scenarios could lead to costly and unnecessary controls w hich do little to reduce risk.

The commenter concluded that because EPA has actual emis sions data from aerospace manufacturing and rework facilities, the Agency can choo se to base its risk assessments solely on these data and the risk assessment would be reasonable, given the other conservative assumptions in the risk analysis.

Response: The EPA disagrees with the commenter's objection to t he EPA’s use of allowable emissions in characterizing risks from the source categ ory. The EPA believes in cases where we are able to quantify allowable emissions that the risk ch aracterization should include such an analyses to help determine the remaining risks (residual risk s) associated with the existing MACT standard. This analysis is necessary to help determine the potential risks to the public as nothing precludes a facility from emitting at the allowabl e level.

Comment: One commenter (0830-0028) agreed with the approach and ration ale EPA used in calculating MACT-allowable emissions for the aerospace industry. The commenter agreed that there have been no advances in control technologies s ince the initial rulemaking and therefore EPA reasonably concluded that actual emissions generally reflect the highest emissions rate expected for modeling purposes. The commenter also agreed wit h EPA’s use of a scaling factor that accounts for the potential for increases in product ion but also caps the effects of increased production at levels that are reasonably expected given aer ospace industry market conditions. The commenter stated that scaling emissions any higher t han this would result in inaccurately high and speculative MACT-allowable risk values. However, the commenter further noted that even if much higher MACT-allowable scaling factors were us ed, the calculated risk would still remain below the presumptively acceptable threshold, for e xample if the modeling assumed 100 percent production utilization the MIR would remain below 20 -in-1 million.

Response: EPA agrees with the commenter that maximum emissions a llowable under the MACT standards (i.e., MACT-allowable emissions) from th e inhalation risk assessment indicate

that the maximum lifetime individual cancer risk could as high as 10 in a million, and that the

maximum chronic non-cancer Hazard Index value is about 0. 5.

Comment: One commenter (0830-0028) agreed that EPA’s finding on facility-wide risk is well below acceptable levels, but stated that this risk should n ot be considered by EPA because CAA Section 112 limits the residual risk review to the regulated source category and requires that each source category be evaluated and regulated separately.

The commenter noted that the statutory language clearly r efers only to the specific MACT source category (or subcategories within that category) being c onsidered, not to the general risks associated with a particular HAP. The commenter furthe r pointed out that the second source of reference established by the Supreme Court is the Conferenc e Report that accompanies legislation at final passage ( Nat’l Assn of Greeting Cards Publishers v. U.S. Postal Serv. [462 U.S. 810, 832 n.28 (1983)]), noting that this Report does not include language on conducting6

facility-wide residual risk determinations but rather mirr ors the statute in referring exclusively to source categories or subcategories [H.R. CONF. REP. NO . 101-952, at 338 (1990)].

The commenter further stated that CAA Section 112(c)(9) shows that Congress was concerned with emissions from specific sources, not facilities, in conducting the residual risk reviews, and therefore EPA cannot exceed its authority by imposing a mo re stringent requirement to address potential and uncertain risks not caused by the sources conte mplated by Congress.

Response: We disagree that examining facility-wide risk in a risk a ssessment conducted under section 112(f) exceeds the EPA’s authority. The developm ent of facility-wide risk estimates provides additional information about the potential cumula tive risks in the vicinity of the RTR sources, as one means of informing potential risk-based deci sions about the RTR source category in question. While we recognize that, because these risk estimates were derived from facilitywide emissions estimates which have not generally been s ubjected to the same level of engineering review as the source category emission estim ates, they may be less certain than our risk estimates for the source category in question, but they remain important for providing context as long as their uncertainty is taken into consi deration in the process.

Section 112(f)(2) of the CAA expressly preserves our use of the two-step process for developing standards to address residual risk and interpret “acceptable r isk” and “ample margin of safety” as developed in the Benzene NESHAP (54 FR 38044, September 14, 1989). I n the Benzene NESHAP, the EPA rejected approaches that would have mand ated consideration of background levels of pollution in assessing the acceptability of ris k, concluding that “...comparison of acceptable risk should not be associated with levels in polluted urban air. With respect to considering other sources of risk from benzene exposure and determining the acceptable risk level for all exposures to benzene, EPA considers this inappropriate because only the risk

associated with the emissions under consideration are relevant to the regulation being established and, consequently, the decision being made.” (54 FR 38044, 38061, Sept ember 14, 1989).

Although not appropriate for consideration in the determi nation of acceptable risk, we note that background risks or contributions to risk from sources outs ide the source category under review

could be one of the relevant factors considered in the ample margin of safety determination, along with cost and economic factors, technological fe asibility, and other factors. Background

risks and contributions to risk from sources outside the f acilities under review were not considered in the ample margin of safety determination for this source category, mainly because of the significant uncertainties associated with emiss ions estimates for such sources. Our approach here is consistent with the approach we took re garding this issue in the Hazardous Organic NESHAP (HON) RTR (71 FR 76603, December 21, 2006), which t he court upheld in the face of claims that the EPA had not adequately consi dered background concentrations. (NRDC v. EPA, 529 F.3d 1077 (D.C. Cir. 2008)).

Comment: One commenter (0830-0028) stated that EPA is appropriate in us ing the 100-in-1 million acceptable risk level as a threshold for determi ning whether additional regulation is needed, referencing the 1987 Vinyl Chloride decision [ NRDC, Inc. v. EPA , 824 F.2d 1146 (D.C. Cir. 1987)] and the decision framework established in the 1989 Be nzene NESHAP [54 Fed. Reg. 38044, September 14, 1989].7

The commenter also noted that EPA appropriately weighed t he costs of increased controls (e.g., add-on controls for primer and topcoat application operatio ns) against the potential benefits of any further reductions in risks in determining whether public health is protected within an ample margin of safety.

The commenter further stated that EPA appropriately con cluded that the risks were acceptable and the current standards are protective within an ample ma rgin of safety such that no additional regulations are necessary under CAA Section 112(f).

Response: The EPA agrees with the commenter that EPA appropriatel y concluded that the risks were acceptable and the current standards are protective wi thin an ample margin of safety.

Comment: One commenter (0830-0028) stated that EPA’s approach to risk analyses results in a hypothetical, upper-bound scenario likely significantly highe r than the risk an actual person would face. The commenter agreed that maximum individual ri sk (MIR) is an estimate of the upper bound of risk based on conservative assumptions, and no ted that EPA’s MIR approach is

conservative at several levels. The commenter further noted that EPA used conservative assumptions and procedures in conducting the acute inhalation exposure assessment, for example assuming that peak emissions will coincide with the worst-c ase wind and atmospheric

conditions.

Response: EPA acknowledges the support of the commenter. For this source category, the risk assessment report included in the docket includes a general discussion of uncertainties and how they have been addressed in the risks characterization.

Comment: One commenter (0830-0030) noted an overall problem that EPA’s entire analysis

seem to be incorrect as it refers to “refineries” ins tead of aerospace facilities. EPA must perform a multipathway risk assessment for aerospace facilitie s in this rulemaking.

Response: EPA disagrees with the commenter that the analysis is based on refineries. The risk characterization, including the multipathway analysis, i s based on emissions from the Aerospace source category. Any references to “refineries” in any of the risk analysis documentation is in

error.

Comment: One commenter (0830-0030) argued that EPA should also conside r reforming risk assessments to support reducing risks to the lowest possibl e level to protect public health. The commenter argued that currently available science challe nges EPA’s assumption because there is so much uncertainty built into the risk assessment, an d because EPA lacks information on so many pollutants. The commenter stated that this policy is especially problematic for communities overburdened by pollution.

The commenter believed that 100-in-1 million lifetime ca ncer risk cannot be considered safe or “acceptable.” The commenter disagreed with EPA basing vari ous types of health risks at that time on an unusual study of people’s perceptions of their o wn risk from 1988, known as the Survey of Societal Risk (July 1988) and should instead be ba sed on scientific information about8

cancer risk. 1 The commenter stated that EPA looked at an odd collect ion of risks, such as dangers from driving a car, and found that “the presumptive le vel established for MIR [maximum individual risk of cancer] of approximately 1 in 10 t housand is within the range for individual risk in the survey, and provides health protection at a level lower than many other

risks common ‘in the world in which we live.’” 2

The commenter recommended that the EPA revisit or update its presumed acceptable level of cancer risk considering information learned about children’s and overburdened community’s vulnerability, biomonitoring and other data on adult body burde ns of chemicals, and new information on ways to analyze and control the impact s of pollutants on human health.

The commenter cited various sources, such as the Nation al Academy of Science's 2009 Science

and Decisions report, which included new information.

The commenter also suggested that EPA review EPA’s Childre n’s Health Protection Advisory Committee (CHPAC) which recommended addressing the develop mental origins of adult disease that come from childhood exposure to air pollution and othe r environmental contaminants. 3 The commenter also suggested that EPA heed CHPAC’s recommenda tion that EPA incorporate a more robust analysis of childhood and pre-natal exposure to environmental contaminants into its

risk assessment method. 4

As urged by the EPA’s Science Advisory Board (SAB), the c ommenter recommended that EPA address the greater risk to children from hazardous air pollut ion. 5 The commenter added that SAB also further explained: “California’s Office of Envir onmental Health Hazard Assessment (OEHHA) has very recently updated its methodology in way s that could affect the development of RfC and URE (unit risk estimate) values. EPA should e xamine these developments to make sure that the RTR process adequately covers children’s risks .” 6

1 Benzene Rule Docket No. OAQPS 79-3, Part I, Docket Item X-B-1, EPA Air Docket (cited at Nat’l Emission Standards for Hazardous Air Pollutants; Benzene Emission s from Maleic Anhydride Plants, Ethylbenzene/Styrene Plants, Benzene Storage Vessels, Benzene Equipment Leaks, and Coke By-Product Recovery Plants, 53 Fed. Reg. 28,496, at 28,512-13 (July 28, 1988)).

2 54 Fed. Reg. 38,044, 38,046 (Sept. 14, 1989) (quotation omitted).

3 EPA, Report of the Task Group of the Children’s Health Protection Advis ory Comm. on America’s Children & the

Environment , 3d Ed. (2010), available at http://www2.epa.gov/sites/production/files/2014- 05/documents/ace_task_group_report.pdf.

4 Letter from Pamela Shubat, Chair, Children’s Health Prot ection Advocacy Council, CHPAC to Lisa Jackson, Administrator, U.S. EPA, (Oct. 21, 2010) (“CHPAC recommends that EPA staff scientists participating in the upcoming discussions bring the concern of early life stage exposure and sensitivity to the conversations that wi ll take place concerning optimizing risk assessment practic e.”), http://yosemite.epa.gov/ochp/ochpweb.nsf/content/CHPAC_NRC_R eport.htm.

5 SAB May 2010 at 7, supra note 77 (stating that “an overarching concern with the A gency’s chronic inhalation exposure estimates is that children’s exposures do not appear to have been adequately addressed”); see also id. at 34 n.13 (“In particular is the question of whether the inter individual variability factor for non-carcinogens and th e standard cancer unit risk derivation adequately covers child ren. If it does not, it is a potentially significant uncertainty given the greater intake rate of children vi a inhalation and sensitivity to carcinogens and other toxicants.”).

6 Id. at 69

The commenter recommended that EPA consider and address c hildren’s health, early life exposure, and cumulative impacts by examining a number of gro undbreaking scientific determinations and protocols released by OEHHA during the las t decade, including three final Technical Support Documents on risk assessment and a new 2015 R isk Assessment Manual. 7

The commenter recommended that EPA scientists and scie nce policymakers revisit the outdated assumption EPA makes regarding what level of cancer ris k triggers policy interventions. The commenter supported EPA’s own policy regarding carcinogens r ecognizes that they have no safe threshold of exposure and EPA’s recognition that cancer r isks add up to increase lifetime risk.

Response: As an initial matter, we note that in 1990 Congress codif ied in section 112(f)(2)(B) of the Clean Air Act the approach we use for our residual ri sk analyses. Under that approach, the 100 in 1 million cancer risk is not a bright line indicatin g that risk is “acceptable.” Rather, we consider this health metric in conjunction with a varie ty of health factors and their associated uncertainties to determine whether the risk is acceptable Where we conclude that the risk is not acceptable, we cannot and do not consider costs in requirin g controls to bring risks down to an acceptable level. However, the analysis of whether ris k is acceptable is not the endpoint. Once

we determine that controls are sufficient to ensure tha t risk is acceptable, we again review the health metrics (e.g., cancer and chronic non-cancer ri sks) and their associated uncertainties in conjunction with the costs of controls, technical fea sibility, and other relevant factors, to determine whether additional controls should be required t o provide an ample margin of safety.

We further note that we generally draw no bright lines of acceptability regarding cancer or noncancer risks from source category HAP emissions, and tha t it is always important to consider the specific uncertainties of the emissions and health eff ects information regarding the source category in question when deciding exactly what level of cancer and non-cancer risk should be considered acceptable. In addition the source category-spe cific decision of what constitutes an acceptable level of risk should be a holistic one; that is, it should simultaneously consider all potential health impacts – chronic and acute, cancer and non -cancer, and multipathway, -- along with all their uncertainties, when determining the acce ptable level of source category risk. Experience with source category rulemakings in the past te lls us that this means drawing bright lines for such decision-making is impossible. The Benzene NESHAP decision framework of 1989 acknowledged this; in today’s world, such flexibility is ev en more imperative, because new information relevant to the question of risk acceptability is being developed all the time, and the accuracy and uncertainty of each piece of information must be considered in a weight-ofevidence approach for each decision. This relevant body of information is growing fast (and it will continue to grow faster and faster), necessitating a flexible weight-of-evidence approach that acknowledges both complexity and uncertainty in the simpl est and most transparent way possible. While this challenge is formidable, it is nonethele ss the goal of the EPA’s RTR decision-making, and it is the goal of the risk assessmen t to provide the information to support the decision-making process.

7 See Cal. EPA, OEHHA

, 2015 Health Risk Assessments Manual

, supra note 151; Cal. EPA, OEHHA Technical Support Documents, http://oehha.ca.gov/air/hot_spots/riskguidancedraft2014.html#down load

.10

We disagree with the general comment that the EPA sho uld adopt the Cal OEHHA childprotective scientific approach on deriving health benchmarks. The EPA has an approach for selecting appropriate health benchmark values and in genera l, this approach places greater weight on the EPA-derived health benchmarks than those f rom other agencies. 8 The approach favoring EPA benchmarks (when they exist) has been endors ed by the SAB and ensures use of

values most consistent with well-established and scienti fically-based EPA science policy. The EPA is currently evaluating the most appropriate use for the Cal OEHHA child- specific reference doses. We note that there are currently no suc h values for HAP inhalation, therefore, the current utility may be limited to persistent and bioa ccumulative (PB)-HAP, which may be associated with non-negligible ingestion exposures. Thi s evaluation on the appropriateness of these values in the context of the RTR Program and EPA science policy is necessary prior to using these child-specific reference doses (RfDs).

We also disagree with the comment that the risk asses sment for this source category does not consider the groups that may be most at-risk (e.g., childre n). When the EPA derives exposure

reference concentrations and unit risk estimates for me tal HAP, it also considers the most sensitive populations identified in the available literature , and importantly, these are the values used in our risk assessments (see US EPA, 2002, A Review of the Reference Dose and Reference

Concentration Processes. EPA/630/P-02/002F. Risk Assessment Forum, Washington, DC.

Available online at http://www.epa.gov/raf/publications/pdfs/rfd-final.pdf .) With respect to maternal exposure in utero specifically, we are unaware of literature that would a llow for a robust characterization of risk during this stage of develo pment.

We acknowledge that population subgroups, including children , may have a potential for risk that is greater than the general population due to greate r relative exposure and/or greater susceptibility to the toxicant. The assessments we underta ke to estimate risk account for this potential vulnerability. With respect to exposure, the ris k assessments we perform implicitly account for this greater potential for exposure by assuming lifetime exposure, in which populations are conservatively presumed to be exposed to a irborne concentrations at their residence continuously, 24 hours per day for a full lifetime , including childhood. With regard to children’s potentially greater susceptibility to non-cancer t oxicants, the assessments rely on EPA (or comparable) hazard identification and dose-response val ues that have been developed to be protective for all subgroups of the general population, inc luding children.

For example, a review 9 of the chronic reference value process concluded that t he EPA’s reference concentration (RfC) derivation processes ade quately considered potential susceptibility of different subgroups with specific consideration of childr en, such that the resultant RfC values pertain to the full human population “including sensitive s ubgroups,” a phrase which is inclusive of childhood. With respect to cancer, the EPA uses the age-dependent adjustment factor approach referred to by the commenter, but limits the use of those factors only to carcinogenic pollutants that are known to act via mutagenic mode of acti on (MOA), in contrast to the OEHHA approach, which uses them across the board for all carci nogens regardless of MOA. In lieu of chemical-specific data on which age or life-stage specifi c risk estimates or potencies can be

8 http://www.epa.gov/ttn/atw/nata1999/99pdfs/healtheffectsinfo.pdf

9 U.S. EPA. A Review of the Reference Dose and Referenc e Concentration Processes. U.S. Environmental Protection Agency, Risk Assessment Forum, Washington, D C, EPA/630/P-02/002F, 2002.11

determined, default age dependent adjustment factors can be applied when assessing cancer risk for early-life exposures to chemicals which cause cancer through a mutagenic MOA.

The estimated risks must be considered in the context of the full set of assumptions used for this

risk assessment. Our unit risk estimates for HAP are co nsidered a plausible upper-bound estimate with an appropriate age dependent adjustment; actual potency i s likely to be lower and some of

which could be as low as zero. Our chronic noncancer refe rence values have been derived considering the potential susceptibility of different subgr oups, with specific consideration of children. In addition, an extra uncertainty factor is n ot needed in the RfC/RfD methodology because the currently available factors are considered su fficient to account for uncertainties in

the database from which the reference values are derived. After considering these and other factors, we continue to consider the risks from emis sions for this source category to provide an ample margin of safety (consistent with the Benzene NESHAP framework).

Comment: One commenter (0830-0030) stated that EPA has underestimate d health risks by underestimating HAP emissions, claiming that EPA did not collect emission test data from the majority of sources in the aerospace source category a nd has given no reasonable explanation for not doing so. The commenter claimed the sources from w hich data were collected comprise less than 10 percent of the existing sources and as a result, E PA’s data inventory memo shows significant reliance on assumptions, some of which have n o real-world basis. The commenter also noted that the EPA asked the facilities to provide a factor to compare their actual and “allowable” emissions, and then argued that rather than perform its regulatory responsibility, the EPA allowed the regulated entities to provide their own nu mber that EPA then used to regulate. The commenter asserted that EPA must provide a reasonabl e explanation of how its estimates represent real-world emissions from aerospace facilitie s or collect additional emission test data to assure its inventory is accurate.

Response: We disagree with the commenter that we have underest imated the health risks by underestimating HAP emissions. The EPA’s method of coll ecting the emissions data for the facilities is explained in the memorandum in the docket d ocumenting the development of the risk modelling database. 10 The emissions of organic HAP from coating operations (i ncluding primers, top coats, chemical milling maskants, and specialty coa tings) were based on the organic HAP content of the coatings and the conservative assumptio n that 100 percent of the organic HAP would be emitted, except in cases where add-on controls were used. In the latter cases, the EPA made conservative assumptions for the capture and contro l efficiency of the spray booths and add-on controls consistent with prior EPA experience wit h these types of controls in other surface coating source categories. The emissions of in organic HAP from coating operations were based on the inorganic HAP content of the coatings, an d assumptions for the transfer efficiency of spray guns, the capture efficiency of spray booths, an d the control efficiency of spray booth filter systems, again consistent with prior EPA experi ence with these types of controls in other surface coating source categories.

We also disagree with the commenter’s implication th at the EPA had incomplete data for the risk assessment. Although the EPA requested stack testing data onl y from select facilities

10 Memorandum: Aerospace Manufacturing and Rework Facilities RTR Modeling File Preparation, December 2014. EPA Docket Item Number EPA-HQ-OAR-2014-0830-0006.12

representing less than 10 percent of existing source facilities, the EPA collected detailed

emissions data from all known facilities in the sourc e likely to be subject to subpart GG through the ICR. The EPA supplemented these data with the stack testing data and through data from other sources, such as the National Emission Inventory (NEI) as described in the RTR Modeling File Preparation memo described above. Further, as expla ined in the preamble for the final rule, in response to our proposal, EPA received only two correctio ns affecting two emission sources at one facility in the risk modeling database and both corre ctions reduced the emissions from that one facility. We note that the commenter did not provi de any additional emissions data.

Finally, as explained in the modelling file documentation memo, the EPA did not use the scaling factors reported by facilities to develop the allowable e mission levels. Instead, the EPA multiplier to estimate maximum allowable emissions was based on the ratio between the 2008 production utilization rate of 83.1 percent and the 20-year his torical maximum production utilization rate of 85 percent.

Comment: One commenter (0830-0030) stated that EPA underestimates he alth risks by not using the best available information on pollutants. The co mmenter claimed that EPA has treated the risk of certain pollutants as zero just because they have not developed a risk measurement for that pollutant – when the science shows there is a ri sk present. The commenter provided the example that EPA failed to evaluate cancer risks from l ead and chloroform despite cancer potency factors that are available from California EPA a nd has given no reasoned explanation for ignoring the carcinogenic risks of these or other polluta nts. In some cases, the commenter claimed EPA inappropriately used values designed for emergency exposure response – values which should not be considered health protective.

The commenter also stated that EPA did not provide public n otice of the HAPs for which it is aware of cancer, chronic non-cancer, acute, or multipat hway risk, for which it did not evaluate

such risk. The commenter claimed this is a violation of notice and comment requirements, and it is unlawful under CAA § 7412(f)(2) for EPA not to assess risk at all from any HAP because it ignores risks EPA knows to exist. The commenter state d that where there is no reference value for a pollutant, EPA must at a minimum add an uncertainty factor to account for the additional risk a HAP likely causes, until such time as EPA has a reference value to use. Using a protective uncertainty factor would allow EPA to satisfy its legal duty under CAA § 7412(f)(2).

Response: This issue was addressed by the EPA’s Science Advisory Boa rd (SAB) in their May 10, 2010, (EPA-SAB-10-007) response to the EPA Administrator. 11 In that response, the SAB panel recommended that, for HAP that do not have dose-r esponse values from the EPA’s list, the EPA should consider and utilize, as appropriate, additiona l sources for such values that have undergone adequate and rigorous scientific peer review. The SA B panel further recommended that the inclusion of additional sources of dose-respons e values into the EPA’s list should be adequately documented in a transparent manner in any residual risk assessment case study. We agree with this approach and have considered other sources o f dose-response data when

11 The SAB peer review of RTR Risk Assessment Methodologi es is available at: http://yosemite.epa.gov/sab/sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File /EPA-SAB-10-007- unsigned.pdf13

conducting our risk determinations under RTR. However, in so me instances no sources of information beyond the EPA’s list are available.

The EPA agrees that we should ultimately develop toxicit y values for all HAP utilizing all credible and relevant toxicity information. The need to update assessments with newly available data as well as the need to complete toxicological asse ssments for all HAP lacking dose-response assessments further increases the importance of Agency activities to streamline and fully utilize the EPA’s already overloaded IRIS program. To that end, t he EPA has always prioritized for future IRIS assessments those HAP without dose-response values but with the greatest potential for public exposure. As a result of this prioritization, w hile not all HAP may have scientifically accepted dose-response values that can be used in residual risk assessments, it is clear that the vast majority of HAP that might carry the potential t o significantly impact the results of residual risk assessments do, in fact, have credible dose-respons e values. Thus, while we are not yet at the point where all HAP have dose-response values, we are gen erally capable of deriving reasonable

risk estimates for those HAP that dominate the risks from any one source category. In the course of each residual risk assessment, should we encounter HAP without dose-response values that carry the potential to create significant risks, we shal l clearly point those out as uncertainties and target them for future IRIS assessments. Moreover, as additional dose-response values become available, the EPA will incorporate these dose-response values into future risk assessments.

The EPA notes that we did state which HAP currently have no reference value. In the risk assessment document, Table 3.1-1 lists all the HAP emitte d by the source category, and indicates whether there is an available cancer, chronic noncanc er, and/or acute dose-response value.

The EPA disagrees with the comment that EPA inappropriately uses values designed for emergency exposure response. The reference values used in this risk assessment for the acute assessments were deemed to represent the best science a vailable to provide an accurate estimate of potential health risks. Our approach is consistent acr oss exposure durations in selecting conservative tools and assumptions to ensure that our decisi ons are protective of human health and the environment. However, only one set of acute refe rence values are most appropriately designed for use in the RTR Program: the acute Reference Exposure Levels (RELs) from California OEHHA which are developed for their Air Toxics Hot Spots program – a program similar in scope and context to the RTR assessments of risk. The one-hour emergency response values available from the Acute Exposure Guideline Level (AE GL) program of EPA and the Emergency Response Planning Guideline (ERPG) value developed by t he American Industrial Hygiene Association provide other values that have been c onsidered for use as comparison values when an acute REL is available, or as the only viable alternative for use when there is no acute REL value for a chemical. When weighing the most appropriate reference values to use on a chemical-specific basis (when more than one is ava ilable), EPA judges the merits of the values on both critical aspects: (1) scientific accuracy and ( 2) being appropriately health protective based on the scientific evidence (i.e., striving to be neither under- nor over-protective).

We disagree with the general comment that the EPA sho uld adopt the California OEHHA acute RELs by default as the best science. The EPA has an a pproach for selecting appropriate health effect reference benchmark values and in general, this appr oach prioritizes according to (1) conceptual consistency with EPA risk assessment guideline s and (2) level of review received that14

is consistent with EPA standards. 12 Notably, this prioritization approach, which favors EPA benchmarks (when they exist), has been endorsed by the SA B; however, SAB also encourages

EPA to review and consider all of the available referenc e values from agencies that employ a derivation method and review process similar to EPA’s. T he EPA is currently evaluating whether it is appropriate to use specific benchmarks values derived by OEHHA on a chemical-bychemical basis by considering: (1) use of the most relev ant scientific evidence as the basis for the value; (2) use of the most appropriate derivation methods (including use of appropriate models, scientifically-based adjustments, and application of un certainty factors); and (3) selecting the most appropriate values for the exposure context.

The EPA does not rely exclusively upon AEGL or ERPG valu es for assessment of acute exposures. Rather, the EPA’s approach is to consider va rious acute health effect reference values (see 80 FR 8402), including the California REL, in assessing the potential for risks from acute exposures. To better characterize the potential health risks associated with estimated acute exposures to HAP, and in response to a key recommendation from the SAB’s peer review of the EPA’s RTR risk assessment methodologies, 13 we generally examine a wider range of available acute health metrics (e.g., RELs, AEGLs) than we do for our chronic risk assessments. This is in response to the SAB’s acknowledgement that there are ge nerally more data gaps and

inconsistencies in acute reference values than there ar e in chronic reference values. In some cases, when Reference Value Arrays 14 for HAP have been developed, we consider additional acute values (i.e., occupational and international values) to provide a more complete risk characterization. As discussed in the preamble to the pro posed rule (80 FR 8402), the exposure guidelines EPA considers depends on which exposure guidelines are available for the various hazardous air pollutants emitted. The EPA uses AEGL and ER PG values (when available) in conjunction with REL values (again, when available) to characterize potential acute health risks. However, it is often the case that HAP do not have all of these acute reference benchmark values. In these instances, the EPA describes the potent ial acute health risk in relation to the acute health values that are available. Importantly, wh en interpreting the results, we are careful to identify the benchmark being used and the health implicati ons associated with any specific benchmark being exceeded. Further, when there are gaps in the available information, uncertainty factors (UFs) are applied to derive referenc e values that are intended to be protective against appreciable risk of deleterious effects. Uncertaint y factors are commonly default values 15

12 http://www.epa.gov/ttn/atw/nata1999/99pdfs/healtheffectsinfo. pdf

13 The SAB peer review of RTR Risk Assessment Methodologi es is available at: http://yosemite.epa.gov/sab/sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File/EPA-SAB -10-007- unsigned.pdf

. 14 U.S. EPA. (2009) Chapter 2.9 Chemical Specific Reference Values for Formaldehyde in Graphical Arrays of Chemical-Specific Health Effect Reference Values for Inhalation Exposures (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R–09/061, and availa ble on-line at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=211003

. 15 According to the NRC report Science and Judgment in Risk Assessment (NRC, 1994) “[Default] options are generic approaches, based on general scientific knowledge and policy judgment, that are applied to various elements of the risk-assessment process when the correct scient ific model is unknown or uncertain.” The 1983 NRC repor t Risk Assessment in the Federal Government: Managing the Process defined default option as “the option chosen on the basis of risk assessment policy that appears to be t he best choice in the absence of data to the contrary” (NRC, 1983a, p. 63). Therefore, default options are not rules that bi nd the agency; rather, the agency may depart from them in evaluating the risks posed by a specific substance when it believes this to be appropriate. In keeping with EPA’ s15

(e.g., factors of 10 or 3) used in the absence of compound-spec ific data; where data are available, uncertainty factors may also be developed using compound-speci fic data; where data are available, data-derived extrapolation factors may also b e developed using compound-specific information. When data are limited, more assumptions a re needed and more default factors are used. Thus there may be a greater tendency to overestimat e risk—in the sense that further study might support development of reference values that are hig her (i.e., less potent) because fewer default assumptions are needed. However, for some polluta nts it is possible that risks may be

underestimated.

Comment: One commenter (0830-0030) stated that EPA must recognize th at chronic (noncancer) risk-causing pollutants, in the same way as carcin ogens, have no safe level of human exposure. The commenter asserted that NAS recommends can cer and chronic non-cancer risk assessments use the same approach in order to address the fact that very low levels of noncarcinogen exposures can pose health risks. The commente r provided multiple references to scientific and medical publications supporting this asserti on, including in utero research illustrating the high sensitivity a developing fetus has t o toxic agents at extremely small doses. The commenter concluded, saying EPA needs to evaluate non- cancer chronic risk similarly to cancer risk: recognizing there is no safe level of human exposure.

Response: Chronic non-cancer reference values represent chronic e xposure levels that are intended to be health-protective. That is, EPA and other o rganizations which develop non-cancer reference values (e.g., the Agency for Toxic Substances and Disease Registry – ATSDR) utilize an approach that is intended not to underestimate risk in t he face of uncertainty and variability. As previously explained, when there are gaps in the availa ble information, uncertainty factors (UFs) are applied to derive reference values that are int ended to be protective against appreciable risk of deleterious effects. Uncertainty factors are c ommonly default values 16 (e.g., factors of 10 or 3) used in the absence of compound-specific data; where data are available, uncertainty factors may also be developed using compound-specific data; w here data are available, dataderived extrapolation factors may also be developed using c ompound-specific information. When data are limited, more assumptions are needed and m ore default factors are used. Thus there may be a greater tendency to overestimate risk—i n the sense that further study might support development of reference values that are higher (i.e., less potent) because fewer default

goal of protecting public health and the environment, default assumptions are used to ensure that risk to chemicals is not underestimated (although defaults are not intended to overtly overestimate risk). See EPA 2004 An examination of EPA Risk Assessment Principles and Practices, EPA/100/B-04/001 available at: http://www.epa.gov/osa/pdfs/ratf-final.pdf.

16 According to the NRC report Science and Judgment in Risk Assessment (NRC, 1994) “[Default] options are generic approaches, based on general scientific knowledge and policy judgment, that are applied to various elements of the risk-assessment process when the correct scient ific model is unknown or uncertain.” The 1983 NRC repor t Risk Assessment in the Federal Government: Managing the Process defined default option as “the option chosen on the basis of risk assessment policy that appears to be t he best choice in the absence of data to the contrary” (NRC, 1983a, p. 63). Therefore, default options are not rules that bi nd the agency; rather, the agency may depart from them in evaluating the risks posed by a specific substance when it believes this to be appropriate. In keeping with EPA’ s goal of protecting public health and the environment, default assumptions are used to ensure that risk to chemicals is not underestimated (although defaults are not intended to overtly overestimate risk). See EPA 2004 An examination of EPA Risk Assessment Principles and Practices, EPA/100/B-04/001 available at: http://www.epa.gov/osa/pdfs/ratf-final.pdf.16

assumptions are needed. However, for some pollutants it is possible that risks may be

underestimated.

Unlike linear dose-response assessments for cancer, non -cancer health hazards generally are not expressed as a probability of an adverse occurrence. Inste ad, “risk” for non-cancer effects is expressed by comparing an exposure to a reference level as a ratio. The “hazard quotient” (HQ) is the estimated exposure divided by a reference level (e.g. , the RfC). For a given HAP, exposures at or below the reference level (HQ ≤ 1) are not likely to cause adverse health effects. As exposures increase above the reference level (HQs i ncreasingly greater than 1), the potential for adverse effects increases. For exposures predicted to be above the RfC, the risk characterization includes the degree of confidence ascribed to the RfC values for the compound(s) of concern (i.e., high, medium, or low conf idence) and discusses the impact of this on possible health interpretations.

The risk characterization for chronic effects other th an cancer is expressed in terms of the HQ for inhalation, calculated for each HAP at each census block c entroid. As discussed above, RfCs incorporate generally conservative uncertainty factors in the face of uncertain extrapolations, such that an HQ greater than one does not necessarily s uggest the onset of adverse effects. The HQ cannot be translated to a probability that adverse eff ects will occur, and is unlikely to be proportional to adverse health effect outcomes in a popul ation.

Comment: One commenter (0830-0030) claimed that EPA underestimates ri sks to children and from early-life exposure and that EPA must follow the science and account for increased earlylife susceptibility by using age-dependent adjustment factors f or all carcinogens emitted by a source category. The commenter stated that currently, EPA only applies these factors to those HAP included in EPA’s list of carcinogens that act by a mutagenic mode of action and that NAS recognized this as a “missing” default in EPA’s approach th at it should address and account for.

Response: With respect to cancer, the EPA uses the age-dependent adj ustment factor approach referred to by the commenter, but limits the use of thos e factors only to carcinogenic pollutants that are known to act via mutagenic mode of action (MOA). In lieu of chemical-specific data on which age or life-stage specific risk estimates or potenc ies can be determined, default age dependent adjustment factors can be applied when assessing c ancer risk for early-life exposures to chemicals which cause cancer through a mutagenic MOA. Wit h regard to other carcinogenic pollutants for which early-life susceptibility data are l acking, it is the Agency’s long-standing science policy position that use of the linear low-dose extrapolation approach (without further adjustment) provides adequate public health conservatism in t he absence of chemical-specific data indicating differential early-life susceptibility o r when the mode of action is not mutagenicity. 17 The basis for this methodology is provided in the 2005 Supplem ental

Guidance. 18

17 U.S. EPA. A Review of the Reference Dose and Reference Concentration Proce sses. U.S. Environmental Protection Agency, Risk Assessment Forum, Was hington, DC, EPA/630/P-02/002F, 2002.

18 U.S. EPA. (2005), Supplemental Guidance for Assessing Susceptibility from Early-Lif e Exposure to Carcinogens

. EPA/630/R-03/003F. Washington, DC. Available online at: http://www.epa.gov/cancerguidelines/guidelinescarcinogen-supplement.htm.17

The estimated risks must also be considered in the con text of the full set of assumptions used for

this risk assessment. Our unit risk estimates for HAP ar e considered a plausible upper-bound estimate with an appropriate age dependent adjustment; actua l potency is likely to be lower and

some of which could be as low as zero.

Comment: One commenter (0830-0030) claimed that EPA’s risk assessmen t does not take into account increased susceptibility to carcinogens due to pre-n atal exposures, even for known mutagenic carcinogens. The commenter stated that NAS iden tified the lack of accounting for in

utero periods of exposure as a major omission in the EPA’s 2005 cancer guidelines. Similarly,

the commenter noted that OEHHA conducted its own review o f scientific literature on pre-natal susceptibility and exposures, which EPA should also consult and use. The OEHHA discusses the use of a 10X adjustment factor for cancer risk to account for pre-natal to age 2 exposures and the

commenter asserts EPA should use that same factor to as sess health risk due to pre-natal

exposure.

Response: We disagree with the commenter in that the risk asses sment for this source category does not consider the groups that may be most at-risk (e.g. , children). When the EPA derives exposure reference concentrations and unit risk estimates for hazar dous air pollutants, it also considers the most sensitive populations identified in the avail able literature, and importantly, these

are the values used in our risk assessments. 19 With respect to maternal exposure in utero specifically,

we are unaware of literature that would allow for a robust charac terization of risk during this stage of development.

We acknowledge that population subgroups, including children, may have a potentia l for risk that is greater than the general population due to greater relative exposure and/or greater susceptibility to

the toxicant. The assessments we undertake to estimate risk account for this potential vulnerability. With respect to exposure, the risk assessments we perform implic itly account for this greater potential for exposure by assuming lifetime exposure, in which popul ations are conservatively presumed to be exposed to airborne concentrations at their residence continuously, 24 hours per day for a full lifetime, including childhood. When the EPA derives exposure reference concentrations and unit risk estimates for hazardous air pollutants, it c onsiders the most sensitive populations identified in the available literature, and importantly, these are the values used in our risk

assessments. 20 We also disagree with the general comment that the EP A should adopt the Cal OEHHA child-protective scientific approach for deriving heal th benchmarks. The EPA has an approach for selecting appropriate health benchmark values an d in general, this approach places greater weight on the EPA derived health benchmarks than those from other agencies. 21 Additionally, the approach of favoring EPA benchmarks (whe n they exist) has been endorsed by

the SAB and ensures the use of values most consistent w ith well-established and scientificallybased EPA science policy.

With respect to cancer, the EPA uses the age-dependent ad justment factor approach referred to by the commenter, but limits the use of those factors on ly to carcinogenic pollutants that are known to act via mutagenic mode of action, in contrast to the OEHHA approach, which uses

19 US EPA. (2002). A review of the reference dose and refere nce concentration processes. EPA/630/P-02/002F. Risk Assessment Forum, Washington, DC. Available online at http://www.epa.gov/raf/publications/pdfs/rfd-final.pdf

20 Id.

21 http://www.epa.gov/ttn/atw/nata1999/99pdfs/healtheffectsinfo. pdf18

them across the board for all carcinogens regardless of mode of action (MOA). In lieu of chemical-specific data on which age or life-stage specifi c risk estimates or potencies can be determined, default age dependent adjustment factors can be applied when assessing cancer risk for early-life exposures to chemicals which cause cancer through a mutagenic MOA. With regard to other carcinogenic pollutants for which early-life susce ptibility data are lacking, it is the Agency’s long-standing science policy position that use of the linear low-dose extrapolation approach (without further adjustment) provides adequate public he alth conservatism in the absence of chemical-specific data indicating different ial early-life susceptibility or when the mode of action is not mutagenicity. 22 The basis for this methodology is provided in the 2005 Supplemental Guidance. 23

Comment: One commenter (0830-0030) stated that most of EPA’s IRIS t oxicity values used for chronic non-cancer risk assessment do not incorporate the latest science on the increased susceptibility of children and EPA should apply child-specific reference values, where available, to evaluate chronic non-cancer risks. Specifically, the commenter points to nickel, cadmium, manganese, and lead; all of which EPA has recognized are emitted by aerospace facilities. The commenter claimed that OEHHA has generated child-specific reference values for several pollutants based on the latest science to take into accoun t children’s greater exposure and greater vulnerability and EPA should use these values in its risk assessments.

The commenter also stated that where child-specific ref erence values are unavailable, EPA must consult science on early exposure impacts and use an additional default or uncertainty factor to account for increased risk from early-life exposures for non-cancer risk. The commenter pointed to the 10X factor enacted by Congress in the Food Quality Protection Act (FQPA) of 1996 and stated that it would be appropriate and within EPA’s authority under CAA § 7412(f)(2) to similarly use a children’s ten-fold margin of safety f actor to fulfill the CAA’s “margin of safety” requirement. The commenter went on to state that EPA can have no valid basis for ignoring science showing that pollutants other than carcinogens a lso can cause substantial harm even at low doses if exposure occurs in utero and during the early years of vulnerability.

Response: We disagree with the commenter in that the risk asses sment for this source category does not consider the groups that may be most at-risk (e.g. , children). When the EPA derives exposure reference concentrations and unit risk estimates for hazardous air pollutants, it considers the most sensitive populations identified in the available literature, and importantly,

these are the values used in our risk assessments. 24 We also disagree with the general comment that the EPA should adopt the Cal OEHHA child-protective scientific approach for deriving health benchmarks. The EPA has an approach for selecting appropriate health benchmark values and in general, this approach places greater weight on th e EPA derived health benchmarks than those from other agencies. 25 Additionally, the approach of favoring EPA benchmarks (whe n they

22 U.S. EPA. A Review of the Reference Dose and Referenc e Concentration Processes. U.S. Environmental Protection Agency, Risk Assessment Forum, Washington, D C, EPA/630/P-02/002F, 2002

23 U.S. EPA. (2005), Supplemental Guidance for Assessing Susce ptibility from Early-Life Exposure to Carcinogens. EPA/630/R-03/003F. Washington, DC. Available online at: http://www.epa.gov/cancerguidelines/guidelinescarcinogen-supplement.htm.

24 US EPA. (2002). A review of the reference dose and refere nce concentration processes. EPA/630/P-02/002F. Risk Assessment Forum, Washington, DC. Available online at http://www.epa.gov/raf/publications/pdfs/rfd-final.pdf

25 http://www.epa.gov/ttn/atw/nata1999/99pdfs/healtheffectsinfo. pdf19

exist) has been endorsed by the SAB and ensures the use of values most consistent with wellestablished and scientifically-based EPA science policy. The EPA is currently evaluating the most appropriate use for the Cal OEHHA child-specific re ference doses. We note that there are currently no such values for HAP inhalation, therefore their current utility would be limited to persistent and bioaccumulative PB-HAP, which may be ass ociated with non-negligible ingestion exposures. The evaluation of the appropriateness of these values in the context of the RTR Program and EPA science policy is necessary prior to usi ng these child-specific reference doses (RfDs).

The EPA also disagrees with the commenter in that a c hildren’s default safety factor of 10 or more should be added to EPA’s reference values. In respon se to the 10X factor enacted by Congress in the Food Quality Protection Act (1996) 26 to the EPA non-cancer reference value derivation, the Agency evaluated their methods for consi dering children’s risk in the development of reference values. As part of their respon se, the U.S. EPA (i.e. the Science Policy Council and Risk Assessment Forum) established the RfD/RfC Technical Panel to develop a strategy for implementing the Food Quality Protection Ac t (FQPA) and examine the issues relative to protecting children’s health and application o f the 10X safety factor. One of the outcomes of the Technical Panel’s efforts was an in dept h review of a number of issues related to the RfD/RfC process (U.S. EPA 2002). The most critical a spect in the derivation of a reference value pertaining to the FQPA has to do with variation bet ween individual humans and is accounted for by a default uncertainty factor (UF-H) when no chemical-specific data are

available. EPA reviewed the default UF for inter-human variability and found the EPA’s default value of 10 adequate for all susceptible populations, including chil dren and infants. The EPA also recommended the use of chemical-specific data in pre ference to default uncertainty factors when available (US EPA, 1994, 2011) 27 and is developing Agency guidance to facilitate consistency in the development and use of data-derived ext rapolation factors for RfCs and RfDs (U.S EPA, 2011) 28 . Additionally, the EPA also applies a database uncertai nty factor (UF-D) which is intended to account for the potential for deriving an under-protective RfD/RfC as a result of an incomplete characterization of the che mical’s toxicity. In addition to the identification of toxicity information that is lacking, review of existing data may also suggest that a lower reference value might result if addition al data were available.

In conclusion, our chronic noncancer reference values have been derived considering the potential susceptibility of different subgroups, with specifi c consideration of children. In addition, an extra 10X uncertainty factor is not needed in the RfC/RfD methodology because the currently available factors are considered sufficient to account for uncertainties in the database

from which the reference values are derived. After cons idering these and other factors, we continue to consider the risks from emissions after app lication of the revisions to the NESHAP

26 US Environmental Protection Agency, Pesticide: Regulat ing Pesticides. The Food Quality Protection Act (FQPA). 1996. Available at http://www.epa.gov/pesticides/regulating/laws /fqpa/backgrnd.htm.

27 U.S. EPA (1994). Methods for derivation of inhalation refe rence concentrations and application of inhalation dosimetry. (EPA/600/8-90/066F). Research Triangle Park, NC. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=71993

28 U.S. EPA (2011) External Review Draft of Guidance for Ap plying Quantitative Data to Develop Data-Derived Extrapolation Factors for Interspecies and Intraspecies Ex trapolation http://www.epa.gov/raf/DDEF/index.htm20

for this source category to provide an ample margin of sa fety (consistent with the Benzene NESHAP framework).

Comment: One commenter (0830-0030) stated that EPA should utilize th e best science on assessing children’s health risk of exposure to lead, rathe r than considering only the 2008 Lead NAAQS. The commenter stated that aerospace facilities emit at least 200 pounds per year of lead according to EPA’s inventory, yet EPA has assessed heal th risks from lead only by comparison with the 2008 Lead NAAQS. This ignores current data showing that harm, particularly to children, can occur at levels below the 2008 Lead NAAQS. Th e commenter pointed to several sources of new data on lead exposure levels and stated thatEPA’s sole reliance on the 2008 Lead NAAQS is both unlawful and arbitrary due to EPA’s refusal t o consider or address the newer science since 2008 showing harm to children below the exposur e level of the 2008 Lead NAAQS. The commenter claimed EPA has no valid basis or reasoned explanation for not recognizing the need to consider information showing the need to address harm to children at ambient air levels of lead below what the 2008 Lead NAAQS allows.

Further, the commenter stated that EPA found a NAAQS e xceedance on-site at one facility (but no exceedance off-site), suggesting the potential for excee dances at facilities in nearby communities, and that EPA must require emission reduction s of lead to prevent unacceptable

levels of risk from lead.

Response: We disagree with the comment that the use of the lea d NAAQS does not sufficiently protect children. While recognizing that lead has been demonstra ted to exert “a broad array of deleterious effects on multiple organ systems,” the le ad NAAQS targets the effects associated with relatively lower exposures and associated blood lea d levels, specifically nervous system effects in children including cognitive and neurobehavioral ef fects (73 FR 66976). EPA establishes the NAAQS at a level to protect sensitive sub-populations, such as children and pregnant women. The 2008 decision on the lead NAAQS was info rmed by an evidence-based framework for neurocognitive effects in young children. In applying the evidence-based framework, we focused on a subpopulation of U.S. children, those living near air sources and more likely to be exposed at the level of the standard; to the same effect see 73 FR 67000/3-- “The framework in effect focuses on the sensitive subpopu lation that is the group of children living near sources and more likely to be exposed at the l evel of the standard. The evidencebased framework estimates a mean air-related IQ loss f or this subpopulation of children; it does not estimate a mean for all U.S. children”; 73 FR 67005/1--“th e air-related IQ loss framework provides estimates for the mean air-related IQ loss of a subset of the population of U.S. children,

and there are uncertainties associated with those esti mates. It provides estimates for that subset of children likely to be exposed to the level of the stan dard, which is generally expected to be the subpopulation of children living near sources who are likely to be most highly exposed.” In addition, in reviewing and sustaining the lead primary NAAQS, we note that the D.C. Circuit specifically noted that the rule was targeted to protec t children living near lead sources: “EPA explained that the scientific evidence showing the impact of lead exposure in young children in the United States led it ‘to give greater prominence to chi ldren as the sensitive subpopulation in this review’ and to focus its revision of the lead NAAQS on the ‘sensitive subpopulation that is the group of children living near [lead emission] sources an d more likely to be exposed at the

level of the standard.’ Given the scientific evidence o n which it relied, the EPA’s decision to base the revised lead NAAQS on protecting the subset of c hildren likely to be exposed to21

airborne lead at the level of the standard was not arbitrary or capricious.” Coalition of Battery Recyclers, 604 F. 3d at 618.

As noted in the risk assessment document, there is no R fD or other comparable chronic health benchmark value for lead compounds. In 1988, the EPA’s IRIS pro gram reviewed the health effects data regarding lead and its inorganic compounds and dete rmined that it would be inappropriate to develop an RfD for these compounds, stating: 29

A great deal of information on the health effects of l ead has been obtained through

decades of medical observation and scientific research . This information has been assessed in the development of air and water quality criteria by the Agency’s Office of Health and Environmental Assessment (OHEA) in support of re gulatory decision-making by the Office of Air Quality Planning and Standards (OAQPS) a nd by the Office of Drinking Water (ODW). By comparison to most other environme ntal toxicants, the degree of uncertainty about the health effects of lead i s quite low. It appears that some of these effects, particularly changes in the levels of certain blood enzymes and in aspects of children’s neurobehavioral development, may occur at blood l ead levels so low as to be essentially without a threshold. The Agency’s RfD Work Group discussed inorganic lead (and lead compounds) at two meetings (07/08/1985 and 07/22/1985) and consi dered it inappropriate to develop an RfD for inorganic lead.

With regard to the information identified by the commenters , much of this information was

similar to information available at the time of the 2008 N AAQS decision. For example, in 2005, the CDC recognized the evidence of adverse health effects in children with blood lead levels below 10 micrograms per deciliter (μg/dL), and that there i s no safe level of blood lead in young children (CDC, 2005). The commenter also cites a benchmark analysis by California OEHHA that was completed during the time of the last lead NAAQ S review (Carlisle and Dowling, 2007). The quantitative relationship from this analysis is a correlation of 1 IQ point change with a 1.0 μg/dL change in blood lead is actually a substantially smaller change in IQ per μg/dL blood lead than the slope of 1.75 IQ points per μg/dL blood lead use d in the evidence-based framework that the Administrator relied upon in his 2008 decision on a revised level for the lead NAAQS in 2008 (73 FR 66964). Regarding the CHPAC recommendation on the level and averaging time for the revised NAAQS referenced by the commenter, the s ame comment was made to EPA in January of this year in the context of the current NAA QS review and the same comment was made and considered in the 2008 review, that concluded with the current lead NAAQS.

Comment: One commenter (0830-0030) stated that EPA must fully acco unt for the fact that people can be more vulnerable to toxic pollution due to vario us physiological, societal, demographic, and exposure history differences, and can therefo re experience greater health risk from the same amount of a toxic chemical exposure. EPA found and acknowledged disparity in the risks that aerospace facilities create, with dispr oportionate exposure, and thus risks, falling on

African-American and lower income communities. But EPA has not considered the variability and possible increased vulnerability of different socioecon omic groups into its risk assessment.

29 The EPA’s IRIS assessment for lead and compounds (inorga nic) (CASRN 7439-92-1) can be found at http://www.epa.gov/iris/subst/0277.htm.22

Because aerospace facilities affect communities that a re disproportionately people of color or lower income, EPA cannot ignore this greater risk in it s assessment.

Response: We disagree with the commenter that the EPA has ign ored variability of different socioeconomic groups in their exposure and vulnerability to air pollution in the residual risk analysis. The EPA considers all people regardless of r acial or socioeconomic status in the analysis. However, we are not able to determine the base line health status of individuals or communities in a national rulemaking. Individual privacy issues as they relate to health records

and the costs that would be associated with such an anal ysis make the analysis infeasible. Through the EPA’s interim guidance on Environmental Justi ce and the Action Development Process, the agency rule writers and policy makers could look at the whole range of factors that impact communities and population groups when crafting rules . The EPA is continuing to discuss and develop pilot approaches that are consistent with the agency’s responsibilities regarding environmental justice as outlined in EO 12898. In dete rmining the need for tighter residual risk standards, the EPA strives to limit to no hig her than 100-in-1 million the estimated cancer risk for persons living near a plant if exposed to the maximum pollutant concentration for 70 years and to protect the greatest number of persons to an individual lifetime risk of no higher than 1-in-1 million. Considerations are made for all pe ople regardless of racial or socioeconomic

status.

Under EO 12898, the EPA is directed to the greatest extent practicable and permitted by law, to make environmental justice part of its mission by identifyi ng and addressing, as appropriate, disproportionately high and adverse human health or envir onmental effects of its programs, policies and activities on minority populations and low-i ncome populations in the United States.

Consistent with EO 12898 and the Presidential Memorandum th at accompanies it, the EPA’s environmental justice policies promote justice by focusing attention and EPA efforts on addressing the types of environmental harms and risks that ar e prevalent among minority, lowincome and indigenous populations. EO 12898 and the EPA’s environme ntal justice policies do not mandate particular outcomes from an action, but th ey demand that decisions involving the action be informed by a consideration of environmental just ice issues. With respect to this rule,

the EPA found the overall level of risk from the source category to be acceptable and to provide an ample margin of safety for all populations in clos e proximity to these sources, including minority and low-income populations.

Comment: One commenter (0830-0030) stated that EPA must follow the best available science to assess multipathway risk. Specifically, the commente r added that EPA must assess the noninhalation-based risk by aerospace facilities’ emissions of all persistent and all bioaccumulative pollutants. The commenter stated that EPA has restrict ed its multipathway risk screening assessment to only those contaminants identified in the “outdated” 2004 Risk Assessment Guidance as persistent and bioaccumulative in the environm ent (PB-HAPs). This decision is not supported by EPA’s own 2004 Guidance which states that “multipath way risk assessment may be appropriate generally when air toxics that persist and w hich also may bioaccumulate and/or biomagnify are present in releases.” The commenter co ncluded that EPA’s list of 14 PB-HAPs is incomplete, however, because it ignores other HAPs which present a multipathway risk.

The commenter stated the following pollutants have been s hown to have a significant potential for deposition and retention within the environment: arsenic , hexavalent chromium, nickel,23

beryllium, selenium, and naphthalene. The commenter ex plained that air emissions of these compounds therefore present a risk to nearby communities vi a dermal, ingestion, and other noninhalation pathways that are currently not being conside red in the residual risk assessment. The commenter argued that the choice to exclude those contami nants which persist and accumulate in

soils underestimates risks from HAP emissions. In addit ion, the commenter stated that manganese is a pollutant to which children have particular exposure and vulnerability due to elevated levels in soils around major emission sources.

The commenter (0830-0030) stated that EPA must perform multi pathway assessments for all pathways of exposure, including those that particularly af fect children. The commenter further stated that EPA should recognize that science shows additional pathways that it has not addressed for certain pollutants for which it does not rec ognize the need for a multipathway assessment. According to the commenter, science shows that EPA has relied on outdated estimates of incidental soil exposures. The commenter a dded that risk assessments of exposure to soil contaminants should evaluate both direct exposure, ha nd-to-mouth, and indirect, object-tomouth exposure. The commenter cited multiple studies sh owing the rates of hand-to-mouth and object-to-mouth exposure in children toddlers and children, inc luding the 2011 update to EPA’s Exposure Factors Handbook which includes more recent esti mates of hand-to-mouth behavior and should be used by EPA to assess risks from exposures to c ontaminated soils.

Response: We believe our multipathway assessment is a reasonabl e technical analysis of risk to human health from aerospace emissions of HAP via non-i nhalation pathways. We currently do not have screening values for some persistent and bioaccu mulative hazardous air pollutants (PBHAP), but we disagree that the multipathway assessment is inadequate because it did not include some hazardous air pollutants. In the Air Toxics Risk Ass essment Reference Library, we developed the current PB-HAP list considering all of the a vailable information on persistence

and bioaccumulation. 30 In developing the list we considered HAP identified as P B-HAP by other EPA Program Offices (e.g., the Great Waters Pro gram), as well as information from the persistent, bioaccumulative and toxic (PBT) profiler (s ee http://www.pbtprofiler.net). Considering this list was peer-reviewed by the SAB and found to be acceptable, we believe it to be reasonable for use in the RTR program. Based on these sources and the limited available information on the persistence and bioaccumulation of other HAP, we do not believe that the potential for multipathway risk from other HAP rises to the level of the PB-HAP currently on the list. However, in the future we may add more pollutants to the multipathway analysis if we determine it is appropriate to do so.

We disagree with the comment that our multipathway ris k assessment does not consider children. The multipathway screening scenario is intended to represen t a high-end exposure for children via incidental soil ingestion. The 2011 Exposure Factors Handbo ok recommended “upperpercentile” soil ingestion rate (numeric percentile no t specified) for children aged 3 to <6 years is 200 mg/d. The EPA also published the Child-Specific Exposure Facto rs Handbook (2008). No additional data or recommendations for child soil ingesti on are presented in this source, and in fact an “upper percentile” value for this parameter is notprovided. Based on these sources, a

30 Air Toxics Risk Assessment Library, Volume I availabl e at http://www2.epa.gov/fera/air-toxics-risk-assessmentreference-library-volumes-1-324

value of 200 mg/d is used in the current RTR multipathway scr eening scenario for the child incidental soil ingestion rate.

The multipathway risk assessment conducted for this source category was a screening-level assessment. (80 FR 8403-06, 8410, 8415, February 17, 2015). The screening assessment used highly conservative assumptions designed to ensure that fac ilities with results below the screening threshold values did not have the potential for m ultipathway impacts of concern. The screening scenario is a hypothetical scenario, and due to the theoretical construct of the screening model, exceedances of the thresholds are not directly t ranslatable into estimates of risk or hazard quotients for these facilities. The tiered screening approac h used the full multipathway assessment conducted to develop the screening thresholds, but incorporated some site-specific information to replace some default parameters, such as distance to the lake and local meteorological data. The scope of the assessment did not change across the tiers in the multipathway screening assessment and are described in the risk assessment document (and related appendices) available in the docket.

Further, regarding incidental soil contamination, the EPA has estimated risks from both direct and indirect pathways. Direct routes of exposure include di rect ingestion of soil and exposure through dermal contact. However, because it has been demo nstrated in past analyses that exposure levels associated with dermal contact are but a small fraction of exposure levels associated with ingestion and inhalation pathways, dermal exposures were not assessed for this
source category.

Comment: One commenter (0830-0030) stated that EPA must assess mul tipathway risk based on allowable emissions, not just the so-called actual emi ssions which are likely underestimated. EPA has recognized greater amounts of inhalation-based poll utants but has not recognized or assessed the full potential for persistent or bioaccumula tive emissions by failing to assess the potential for greater amounts of other PB-HAP emissions. Intermittent or short spikes of PBHAPs can represent a significant health risk because t he contaminants stay in the environment and can accumulate over time. For this reason, the co mmenter stated that EPA’s analysis likely underestimates the health risks from multipathway routes of exposure.

Response: We disagree with the commenter’s assertion that we s hould base the multipathway

risk assessment on allowable emissions and maintain tha t it is reasonable for the multipathway

risk assessment to be based on actual emissions for thi s source category, and not the allowable level of emissions that facilities are permitted to e mit. The uncertainties associated with the multipathway screening analysis along with uncertainties in the allowable emissions estimates, would make a quantitative multipathway risk assessment bas ed on allowable emissions highly uncertain. However qualitatively, as seen when examining the risk analysis for inhalation, because emissions for both actual and allowable are compar able, we would expect a multipathway analysis considering allowable to be simil ar to that for actual emissions (all facilities passed the Tier 1 screening analysis).

Comment: One commenter (0830-0030) stated that EPA must account for the aggregate impact of inhalation and multipathway cancer and chronic non-ca ncer risk by adding each type of similar risk together for all pollutants. The multipath way assessment allows EPA to look at a person’s overall exposure – not just inhalation. EPA must add multipathway and inhalation risk.25

Failing to determine cancer risks, non-cancer risks, and a cumulative burden metric makes EPA’s overall analysis incomplete.

Response: We disagree with the commenter’s assertion that our risk analysis is incomplete and have combined risk to the extent that it is appropriate to d o so. We consider the effect of mixtures of carcinogens consistent with EPA guidelines and use a target organ-specific hazard index (TOSHI) approach for our chronic non-cancer assess ments. We do not use a TOSHI approach for acute analyses nor do we combine the result s of our inhalation and multipathway

assessments. We did not find it reasonable to combine the results of our inhalation and multipathway risk assessment for this source category. The multipathway risk assessment was a screening-level assessment. The screening assessment used hi ghly conservative assumptions designed to ensure that facilities with results below the screening threshold values did not have the potential for multipathway impacts of concern. The screening scenario is a hypothetical scenario, and due to the theoretical construct of the sc reening model, exceedances of the thresholds are not directly translatable into estimate s of risk or hazard quotients for these facilities. Rather, it represents a high-end estimate of what the risk or hazard may be. For example, an exceedance of two for a non-carcinogen can be interpreted to mean that we have high confidence that the hazard would be less than two. Sim ilarly, an exceedance of 30 for a carcinogen means that we have high confidence that the ri sk is lower than 30-in-1 million. Our confidence comes from the conservative, health-protecti ve assumptions that are in the screens: we choose inputs from the upper end of the range of possible values for the influential parameters used in the screens; and we assume that the exposed individual exhibits ingestion behavior that would lead to a high total multipathway exposur e. We do not sum the risk results from chronic inhalation assessment and the screening mul tipathway assessment because it is inappropriate to do so based on the differences in the two t ypes of assessments. In addition to the constraints in the screening-level multipathway assessm ent described above, it is high ly unlikely that the same receptor has the maximum results in both assessm ents. In other words, it is unlikely that the person with the highest chronic inhalation canc er risk is also the same person with the highest individual multipathway cancer risk. We agree, in concept, with the commenter that we should consider overall risk, but we do so by assessing cancer and chronic non-cancer inhalation risk, acute risk, multipathway risk and by combining risk re sults where appropriate, not by arbitrarily summing risk measures in the absence of a val id technical basis.

Comment: One commenter (0830-0030) disagreed with the findings that th e health risks presented by aerospace facilities are acceptable. The com menter stated that EPA findings of at least 10-in-1 million lifetime cancer risk, with 180,000 people exposed to a risk of 1-in-1 million or more, is an extra cancer case at least every 50 ye ars. The commenter argued that EPA should not find that this extra cancer case is “acceptable” and no community member should have to

have their child or other loved one become this statisti c.

The commenter added that the acute risk hazard quotient (“H Q”) of 2, which is twice the HQ where EPA believes no harm occurs, is under-protective and unreliable. The commenter argued that there is a good chance that this high acute risk als o occurs in other communities near other facilities that are located nearer to people and EPA ha s provided no evidence showing this is not

the case.26

The commenter stated that all of these risks occur dis proportionately in communities of color and lower income communities – many of whom are experiencing other toxic pollution simultaneously on top of this pollution.

Response: In 1990, Congress codified in section 112(f) of the CAA the approach we use for our residual risk analyses (i.e., the Benzene NESHAP, 54 FR 38044) . Under that approach, the 100- in-1 million cancer risk is not a bright line indicating t hat risk is “acceptable.” Rather, we consider this health metric in conjunction with a varie ty of health factors and their associated uncertainties to determine whether the risk is acceptable. Where we conclude that the risk is not acceptable, we cannot and do not consider costs in requirin g controls to bring risks down to an acceptable level. However, the analysis of whether ris k is acceptable is not the endpoint. Once we determine that the existing MACT standards or controls are sufficient to ensure risk is acceptable, we again review the health metrics (e.g., ca ncer and chronic non-cancer risks) and their associated uncertainties in conjunction with the costs of controls, technical feasibility, and other relevant factors, to determine whether additional c ontrols should be required to provide an ample margin of safety. As explained at proposal, EPA has adopted the Benzene NESHAP approach in its residual risk determinations and the D.C. C ircuit has upheld as reasonable the EPA’s interpretation that section 112(f)(2) incorporates t his approach. NRDC v. EPA, 529 F. 3d 1077, 1083 (D.C. Cir. 2008) (“[S]ubsection 112(f)(2)(B) expressly inc orporates the EPA’s interpretation of the Clean Air Act from the Benzene standard, complete with the citation to the Federal Register.”).

We generally draw no bright lines of acceptability regard ing cancer or non-cancer risks from source category HAP emissions, and it is always import ant to consider the specific uncertainties of the emissions and health effects information regard ing the source category in question when deciding exactly what level of cancer and non-cancer risk should be considered acceptable. In addition, the source category-specific decision of what constitutes an acceptable level of risk should be a holistic one; that is, it should simultane ously consider all potential health impacts -- chronic and acute, cancer and non-cancer, and multipathwa y -- along with their uncertainties, when determining the acceptable level of source category r isk. In other words, we look at the risk numbers within the context of uncertainty associated wi th emissions and health benchmark

values. The Benzene NESHAP decision framework of 1989 acknow ledged this; in today’s world, such flexibility is even more imperative, because new information relevant to the question of risk acceptability is being developed all the time, and t he accuracy and uncertainty of each piece of information must be considered in a weight-of - evidence approach for each decision. This relevant body of information is growing fast (and w ill continue to grow even faster), necessitating a flexible weight-of-evidence approach that acknowledges both complexity and uncertainty in the simplest and most transparent way po ssible. While this challenge is formidable, it is nonetheless the goal of the EPA’s RTR decision-making, and it is the goal of the risk assessment to provide the information to support the de cision-making process.

Comment: One commenter (0830-0031) recommended that the EPA consider allowable or potential emissions, rather than actual emissions, as m uch as possible for evaluating risks

because actual emissions could increase over time and coul d underestimate residual risk. The commenter supported the EPA's use of allowable emissions in parts of the rulemaking, but noted that EPA used actual emissions in other parts, and encourage d EPA to use allowable emissions, including in assessing acute health risks.27

Response: Consistent with previous risk assessments, the EPA con siders both allowable and actual emissions in assessing chronic risks under CAA sec tion 112(f)(2). (See, e.g., National Emission Standards for Coke Oven Batteries (70 FR 19998-19999, Apri l 15, 2005); proposed and final National Emission Standards for Organic Hazardous Air Pollutants from the Synthetic Organic Chemical Manufacturing Industry (71 FR 34428, June 14, 2006, an d 71 FR 76603, December 21, 2006). This approach is both reasonable and consis tent with the flexibility inherent in the Benzene NESHAP framework for assessing a cceptable risk and ample margin of safety. As a general matter, modeling allowable emission levels is inherently reasonable since

this reflects the maximum level sources could emit and st ill comply with national emission

standards. But it is also reasonable to consider actual e missions, where such data are available, in the acceptable risk and ample margin of safety analyses . See National Emission Standards for Coke Oven Batteries, 70 FR 19992, 19998 (April 15, 2005). The risk asses sment for the aerospace manufacturing and rework (surface coating) sourc e category was conducted using actual and allowable emissions, and all of the results w ere considered in determining risk acceptability and ample margin of safety. See the Resi dual Risk Assessment for the Aerospace Manufacturing and Rework Facilities Source Category in Suppo rt of the November, 2015 Risk and Technology Review – Final, available in the docket for this rulemaking.

The commenter also urges the Agency to rely on allowable emissions for the purpose of our acute assessment. We did not rely on allowable emissio ns for the acute screening assessment due to the conservative assumptions used to gauge worst-case potent ial acute health effects. The conservative assumptions built into the acute health ris k screening analysis include: (1) use of peak 1-hour emissions that are on average ten times the a nnual average 1-hour emission rates; (2) that all emission points experience peak emissions c oncurrently; (3) worst-case meteorology (from 1 year of local meteorology); and (4) that a pers on is located downwind at the point of maximum impact during this same 1-hour period. Thus, performing a n acute screen based on allowable emissions would be overly conservative and at b est, of questionable utility to decision

makers.

Comment: One commenter (0830-0031) recommended that the EPA consider the emission concentration at the fenceline of the facility, rath er than at the centroid of the most highly affected census block when assessing the cancer risk. The commenter noted that the point of maximum impact could be located far from the centroid of t he census block, depending on the size and population density of the census block. The comment er also noted that over time homes and businesses could be built closer to the facility. Th e commenter also noted that using HEM-3, the EPA can locate the maximum individual risk at any poin t in the census block and

recommended that the EPA should use the truly maximum individual risk, rather than the risk at the centroid of the census block as a surrogate for exposure to all people in the census block, in the EPA's CAA section 112(f)(2) risk assessments.

Response: In a national-scale assessment of lifetime inhalation exposures and health risks from facilities in a source category, it is appropriate to ide ntify exposure locations where it may be reasonably expected that an individual will spend a majority of his or her lifetime. In determining chronic risks, it is appropriate to use census block informa tion on where people actually reside, rather than points at the property line, to locate the estimation of exposures and risks to individuals living near such facilities. Census blocks are th e finest resolution available as part of the nationwide population data (as developed by the US Censu s Bureau); on average, a census28

block is comprised of approximately 40 people and about 10 household s. In the EPA risk assessments, the geographic centroid of each census block containing at least one person is used to represent the location where all the people in thatcensus block live. The census block centroid with the highest estimated exposure then becomes the loc ation of maximum exposure, and the entire population of that census block is assumed to experi ence the maximum individual risk. In some cases, because actual residence locations may be cl oser to or farther from facility emission points, this may result in an overestimate or underesti mate of the actual annual concentrations (although there is no systematic bias for average level s). Given the relatively small dimensions of census block in densely-populated areas, there is little uncertainty introduced by using the

census block centroids in lieu of actual residence locatio ns. There is the potential for more uncertainty when the census block are larger, although there is still no systematic bias. The EPA concludes that the most appropriate locations at which to estimate chronic exposures and risks are the census block centroids because: 1) census blocks are the finest resolution available in the national census data; 2) facility fence lines do not typ ically represent locations where chronic exposures are likely (i.e., people do not typically live a t the fence line of facilities); and 3) there

is no bias introduced into the estimate of the maximum i ndividual risk (MIR) by using census block centroid locations. In its peer review of the meth odologies used to estimate risks as part of the RTR rulemaking efforts, the EPA’s Science Advisory B oard (SAB) endorsed this approach. 31

This has been the EPA’s approach for estimating chronic m aximum individual exposures and risks throughout the RTR program. In addition, in its pee r review of the methodologies used to estimate risks as part of the RTR rulemaking efforts, the EPA’s Science Advisory Board (SAB) endorsed this approach.

In addition to the approach described above, the EPA recogni zes that where a census block centroid is located on industrial property or is large an d the centroid is less likely to be representative of the block’s residential locations, t he block centroid may not be the appropriate surrogate. For this source category, as described in the r isk assessment document available in the docket, in cases where a census block centroid was within 300 m eters of any emission source (and, therefore, possibly on facility property), we view ed aerial images of the facility to determine whether the block centroid was likely located on facility property. Likewise, we examined aerial images of all large census blocks within one kilometer of any emission source. If the block centroid did not represent the residential loca tions within that block, we relocated it to better represent them and/or we added receptors for resi dences nearer to the facility than the

centroid.

In the case of military operations the census block co uld be located within the facility boundary (i.e., on the military base) in the form of on-base residential housing, and this fact was taken into

account in the risk assessment.

31 U.S. Environmental Protection Agency, Office of the A dministrator Science Advisory Board. Review of EPA’s draft entitled, “Risk and Technology Review (RTR) Risk As sessment Methodologies: For Review by the EPA’s Science Advisory Board with Case Studies – MACT I Petrole um Refining Sources and Portland Cement Manufacturing.” EPA-SAB-10-007. May 7, 2010. http://yosemite.epa.gov/sab/sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File /EPA-SAB-10-007- unsigned.pdf

.29

For this source category, we added several receptors for c ensus blocks where the centroid location was not representative of the residential loc ations. Appendix 4 of the risk assessment, entitled "Residual Risk Assessment for the Aerospace Man ufacturing and Rework Facilities Source Category in Support of the November, 2015 Risk and Te chnology Review – Final," provides additional information on these changes.

Comment: One commenter (0830-0031) shared the EPA's concern about the disproportionate impact on certain social, demographic, and economic groups, but recommended that EPA improve the methods of evaluating environmental justice and asked EPA to consider these factors in developing the final rule. The commenter rec ommended that the EPA conduct the demographic analysis on individuals projected to experience a risk greater than 1-in-1 million

and also on individuals living within 5 kilometers (km) of the fac ility, regardless of projected

risk. The commenter stated that this would be consistent with the approach used for the Hard and Decorative Chromium Electroplating and Chromium Anodiz ing Tanks source category. 32 The commenter noted that the socio-economic analysis for the proposed Aerospace NESHAP did not evaluate potential disparities within 5 km for cancer risk at maximum allowable emission levels and argued that this type of analysis is especially import ant in instances where a facility is located in a minority and low-income community. The co mmenter noted that the EPA only evaluated the risk to the population within a 50 km radius, and argued that this could dilute the results by including populations not in the demographic groups mo st at risk, especially the case if the source is located in or next to a minority or low -income population. Therefore, the commenters recommended that EPA conduct an analysis at the 5 km distance to assess facility impacts to nearby environmental justice communities and that the rule writers work with the EPA Office of Environmental Justice to develop criteria and specific guidance on how to interpret and apply the outcome of these types of analys es in the rulemaking process.

Response: The commenter is correct that we performed the demographi c analyses for the aerospace source category differently than we did for the October 2010 proposed RTR for the Hard and Decorative Chromium Electroplating and Chromium Anodizing Tanks source categories. We performed the demographic analyses for both source categories using two approaches as examples of how such analyses might be de veloped, and invited public comment on the approaches used and the interpretations made from t he results. In the first approach, we focused the analysis on the total populations residing withi n 5 km of each facility, regardless of their estimated risks, and examined the distributions acro ss various demographic groups within those 5 km circles. That analysis was a “proximity” anal ysis in that it considered only the distance from the emission sources to surrounding populatio ns, and not the estimated risks to those populations

In the second approach, we focused the analysis on the popul ations within 5 km of any facility estimated to have exposures to HAP that result in cancer risks of 1-in-1 million or greater or noncancer hazard indices of 1 or greater. We examined the di stributions of those risks across various demographic groups. In each approach, we compared the percentage s of particular demographic groups to the total number of people in those demographic groups n ationwide. We stated in the proposed rule for the Hard and Decorative Chromium Elect roplating and Chromium Anodizing

32 National Emission Standards for Hazardous Air Pollutant Emissions: Hard and Decorative Chromium Electroplating and Chromium Anodizing Tanks; Proposed Rule. 75 FR 65068, October 21, 2010. 75 FR 65089.30

Tanks source categories that in future rules we planned to extend the analyses to cover the entire modeled domain for a facility (50 km radius) to capture all individuals with risks above 1-in-1 million or greater or non-cancer hazard indices of 1 or greater. We also stated that generally we have found that using a 5 km radius in the analysis will capture more than 90 percent of the

individuals with cancer risks above 1-in-1 million.

In the February 2012 supplemental proposal for the RTR for the Hard and Decorative Chromium Electroplating and Chromium Anodizing Tanks source categor ies, our demographic analyses included populations within 50 km of each source (including those very near the sources) with risks of 1-in-1 million or greater or non-cancer hazar d indices of 1 or greater (77 FR 6628, Feb. 8, 2012). We did not include analyses using a 5 km radius in that supplemental proposal nor in the RTR proposal for the aerospace source category. We believe that, where a risk assessment has been performed, it is more informative to consider the demographics of all populations (including those beyond 5 km) with elevated risks than to limit the demographics analysis to populations located within 5 km of a facility. Where a ris k assessment has been performed, these populations are identified, and the source parameters are t aken into account. As discussed above, we have found that most exposure locations with the high est estimated risks are within 5 km of a facility, so extending the radius to 50 km has little im pact on an analysis based on risks, but makes more sense because 50 km corresponds to the risk modeli ng radius and includes all populations with elevated risk estimates. We also note th at we are working with the Office of Environmental Justice in an ongoing effort to develop new too ls for considering environmental justice in rulemakings.

Comment: One commenter (0830-0031) expressed concern with the EPA’s past and current use of Acute Exposure Guideline Levels (AEGLs) or Emergency Res ponse Planning Guidelines (ERPGs) values to address acute exposures in the residual risk assessments. The commenter argued that these limits were developed for accident relea se emergency planning, and are not appropriate for assessing daily human exposure scenarios. The commenter noted that in the December 2002 EPA document, "A Review of the Reference Dos e and Reference Concentration Processes," EPA stated that the primary purpose of the A EGL program is to develop guidelines for once-in-a-lifetime short-term exposures to airborn e concentrations of acutely toxic chemicals, and they are not meant to evaluate the acute impacts fr om routine emissions that occur over the life of a facility. The commenter argued that, unlike t he reference concentrations (RfCs) for chronic exposures, the AEGLs and ERPGs do not include adequate safety and uncertainty factors and cannot be relied upon to protect the public from the adver se effects of exposure to toxic air pollutants. The commenter argued that AEGLs and ERPGs s hould not be used in residual risk assessments because they do not ensure that public health is adequately protected from the acute impacts of HAP exposure. The commenters supported EPA's inc reased use of California Reference Exposure Levels (RELs) to address acute exposures in the residual risk assessments and urged EPA to use the RELs for these assessments.

Response: The EPA does not rely exclusively upon AEGL or ERPG val ues for assessment of acute exposures. Rather, the EPA’s approach is to conside r various acute health effect reference values (see 80 FR 8402), including the California REL, in asse ssing the potential for risks from acute exposures. To better characterize the potential he alth risks associated with estimated acute exposures to HAP, and in response to a key recommendation from the SAB’s peer review of the31

EPA’s RTR risk assessment methodologies, 33 we generally examine a wider range of available acute health metrics (e.g., RELs, AEGLs) than we do for our chronic risk assessments. This is in response to the SAB’s acknowledgement that there are ge nerally more data gaps and

inconsistencies in acute reference values than there ar e in chronic reference values. In some cases, when Reference Value Arrays for HAP have been de veloped, we consider additional acute values (i.e., occupational and international values) to pr ovide a more complete risk characterization. As discussed in the preamble to the pro posed rule (80 FR 8402), the exposure guidelines EPA considers depends on which exposure guidelines are available for the various hazardous air pollutants emitted. The EPA uses AEGL and ER PG values (when available) in conjunction with REL values (again, when available) to characterize potential acute health risks. However, it is often the case that HAP do not have all of these acute reference benchmark values. In these instances, the EPA describes the potent ial acute health risk in relation to the acute health values that are available. Importantly, wh en interpreting the results, we are careful to identify the benchmark being used and the health implicati ons associated with any specific benchmark being exceeded.

Comment: One commenter (0830-0030) argued that the EPA should reform ho w it evaluates chronic and acute hazard indices, in which a risk number b elow 1 does not result in policy changes or standards. The commenter stated that the EP A should instead factor in uncertainties and vulnerability factors to adjust the level of non-cance r risk considered acceptable for both chronic and acute exposure. The commenter added that this i s currently done under the Food Quality Protection Act (FQPA) when EPA uses factors t o determine a Target Margin of Exposure and risks below this level warrant increased scrut iny and changes to allowable

exposures. 34

Response: The EPA’s approach to performing risks assessments in suppor t of the residual risk program has been reviewed and supported by the Science Adviso ry Board (SAB) several times over the past 17 years. 35 Hazard for non-cancer effects is expressed by comparing an exposure to a reference level as a ratio. The “hazard quotient” ( HQ) is the estimated exposure divided by a reference level (e.g., the RfC). For a given HAP, expos ures at or below the reference level (HQ ≤ 1) are not likely to cause adverse health effects. For ex ample, chronic non-cancer reference values represent chronic exposure levels that are intended t o be health-protective. That is, EPA and other organizations which develop non-cancer referenc e values (e.g., the Agency for Toxic Substances and Disease Registry – ATSDR) utilize an approa ch that is intended not to underestimate risk in the face of uncertainty and variabil ity. When there are gaps in the available information, uncertainty factors (UFs) are applied to der ive reference values that are intended to be protective against appreciable risk of deleterious effects.

33 The SAB peer review of RTR Risk Assessment Methodologi es is available at: http://yosemite.epa.gov/sab/sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File/EPA-SAB -10-007- unsigned.pdf

34 See, e.g. , EPA, Sulfuryl Fluoride; Proposed Order Granting Objecti ons to Tolerances and Denying Request for a Stay, Proposed Rule, 76 Fed. Reg. 3422, 3427 (Jan. 19, 2011) (explainin g use of MOE).

35 The SAB peer review of RTR Risk Assessment Methodologi es is available at: http://yosemite.epa.gov/sab/sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File /EPA-SAB-10-007- unsigned.pdf32

We generally draw no bright lines of acceptability regard ing cancer or non-cancer risks from source category HAP emissions. It is always important to consider the specific uncertainties of the emissions and health effects information regarding t he source category in question when decided exactly what level of cancer and non-cancer ris k should be considered acceptable. In addition, the source category-specific decision of what constitutes an acceptable level of risk should be a holistic one; that is, it should simultane ously consider all potential health impacts – chronic and acute, cancer and non-cancer, and multipathwa y, – along with all their uncertainties, when determining the acceptable level of source category r isk. The Benzene NESHAP decision framework of 1989 acknowledged this; in today’s world, such flexi bility is even more imperative, because new information relevant to the ques tion of risk acceptability is being developed all the time, and the accuracy and uncertainty of each piece of information must be considered in a weight-of-evidence approach for each decisi on. This relevant body of information is growing fast (and it will continue to grow faster and faster), necessitating a flexible weight-of-evidence approach that acknowledges both c omplexity and uncertainty in the simplest and most transparent way possible. While this c hallenge is formidable, it is nonetheless the goal of the EPA’s RTR decision-making, and it is the goal of the risk assessment to provide the information to support the decision-making process.

Comment: One commenter (0830-0030) stated that while EPA assesses t he combined impact of cancer risks and chronic non-cancer risk, EPA must also combine and look at the whole picture of all other kinds of risk from multiple pollutants. In particular, EPA must assess the total and synergistic cancer risk and total chronic non-cancer risk for different pollutants. Additionally, the commenter stated EPA should apply these same principles to create a mechanism for assessing

the total acute risk to chemical mixtures. The commente r also stated EPA must create a metric to

assess the total and cumulative risk burden rather than only looking at each type of risk in a discrete, separate way. Unless EPA creates a combined he alth risk metric, it cannot make an ample margin of safety determination that is based on the full picture of health risk for a source category. EPA must assess the cumulative burden for publi c health. The commenter further stated that in addition to performing a cumulative asses sment from multiple sources within the aerospace source category, EPA also must perform a cumu lative analysis that considers the additional risk people face as a result of being exposed to aerospace and also different nearby source categories (not necessarily collocated). The c ommenter claimed EPA has recognized this need but has failed to follow through on evaluating all mu ltiple sources. The commenter stated that while EPA has calculated a “facility-wide” risk fo r different sources collocated at the same address, it has not used that number to set standards and has ignored different sources across the street or in close proximity, even though all these sourc es’ emissions are combining to affect the person most-exposed to aerospace facilities’ emissions. Additionally, EPA has provided no information on how it reached the “facility-wide” ris k number. The commenter provided multiple references (e.g., NAS, OEHHA) and discussion for performing this type of multi-source analysis.

Response: We have combined risk assessment results to the extent t hat it is appropriate to do so and disagree with comment that we failed to consider or account for cumulative risk. The EPA

conducted an assessment of the cumulative cancer risks from all emitted carcinogens and the

cumulative noncancer hazard indices from all emitted n on-carcinogens that are hazardous air pollutants affecting the same target organ system for bot h the source category emissions and the facility-wide emissions. To address the effect of mixtur es of carcinogens, the individual cancer33

risks for the source category were aggregated for all car cinogens. In assessing noncancer hazard from chronic exposures for pollutants that have similar modes of action or that affect the same target organ, we aggregated the hazard quotients (HQ) to provi de a target organ-specific hazard index (TOSHI). We do not use a TOSHI approach for our acute analyses nor do we combine the results of our inhalation and multipathway assessments. We further modeled whole-facility risks for both chronic cancer and non-cancer impacts to unders tand the risk contribution of the sources within the aerospace source category.

For this source category, the EPA conducted an assessmen t of the cumulative cancer risks from all emitted carcinogens and the cumulative noncancer haz ard indices from all emitted noncarcinogens that are hazardous air pollutants affecting the same target organ system for both the source category emissions and the facility-wide emissio ns.

The EPA modeled whole-facility risks for both chronic ca ncer and non-cancer impacts to

understand the risk contribution of the sources within the aerospace source category. The individual cancer risks for the source categories were a ggregated for all carcinogens. In assessing noncancer hazard from chronic exposures for pollutants t hat have similar modes of action or (where this information is absent) that affect the sa me target organ, we aggregated the hazard quotients (HQ). This process creates, for each target orga n, a TOSHI, defined as the sum of hazard quotients for individual HAP that affect the same organ or organ system. All TOSHI calculations presented here were based exclusively on effe cts occurring at the “critical dose” (i.e., the lowest dose that produces adverse health eff ects).

As described in the risk assessment document available in the docket, we do not sum results of

the acute noncancer inhalation assessment to create a combined acute risk number that would represent the total acute risk for all pollutants that ac t in a similar way on the same organ system or systems (similar to the chronic TOSHI). The worst-c ase acute screen is a conservative scenario. That is, the acute screening scenario assumes worst-case meteorology, peak emissions for all emission points occurring concurrently and an ind ividual being located at the site of maximum concentration for an hour. Thus, as noted in “ Residual Risk Assessment for the Aerospace Manufacturing and Rework Facilities Source Category in Support of the November, 2015 Risk and Technology Review - Final ”, because of the conservative nature of the acute inhalation screening and the variable nature of emissions a nd potential exposures, acute impacts were screened on an individual pollutant basis, not using t he TOSHI approach.”

Also, we did not combine the inhalation and multipathway ri sk assessment results for each pollutant because it is inappropriate to do so. The multipa thway risk assessment conducted for proposal was a screening-level assessment followed by a m ore refined site-specific assessment. The screening assessment used highly conservative assumptions designed to ensure that facilities with results below the screening threshold values did not h ave the potential for multipathway impacts of concern. The screening scenario is a hypothetical scenario, and due to the theoretical construct of the screening model, exceedances of the thres holds are not directly translatable into estimates of risk or hazard quotients for these faciliti es. Further, it is unlikely that the person with the highest chronic inhalation cancer risk is also the sa me person with the highest individual multipathway cancer risk.34

We disagree with the claim that additional quantitative assessment of risks from sources outside the source category is required for this rulemaking. Sect ion 112(f) requires the EPA to perform a review of whether there is risk remaining from emission s from a source category after promulgation of the technology based MACT standards for t hat source category. To this end, the EPA conducts a comprehensive assessment of the risks ass ociated with exposure to the HAP emitted by the source category and supplements that with additional information that is available about other possible concurrent and relevant risks. While the incorporation of additional background concentrations from the environment in our risk a ssessments (including those from mobile sources and other industrial and area sources) could be technically challenging, they are neither mandated nor barred from our analysis. In devel oping the decision framework in the Benzene NESHAP currently used for making residual risk dec isions, the EPA rejected approaches that would have mandated consideration of backgro und levels of pollution in assessing the acceptability of risk, concluding that compari son of acceptable risk should not be associated with levels in polluted urban air (54 FR 38044, 38061, Se ptember 14, 1989). Background levels (including natural background) are not barred f rom the EPA’s ample margin of safety (AMOS) analysis, and the EPA may consider the m, as appropriate and as available, along with other factors, such as cost and technical fe asibility, in the second step of its section 112(f) analysis. This assessment excludes background contribut ions because the available data are of insufficient quality upon which to base a meaningfu l analysis. Further, as explained at proposal, our approach here is also consistent with the approach we took regarding this issue in the Hazardous Organic NESHAP (HON) RTR (71 FR 76603, December 21, 2006), which the court upheld in the face of claims that the EPA had not adequately considered background concentrations. (NRDC v. EPA, 529 F.3d 1077 (D.C. Cir. 2008)).

Comment: One commenter (0830-0030) claimed EPA failed to use the best available reference values for a number of key HAPs including benzene, and thus underestimated risk from these pollutants. The commenter provided a comparison table of c ancer potency factors utilized by EPA and those published by California EPA in July 2014. These c omparison showed a significantly lower potency in EPA’s values, ranging fro m 57 percent to 92 percent lower. The

commenter asserted that EPA must use the latest refer ence values in its analysis.

Similarly, the commenter stated that EPA has used som e out of date and less health protective reference inhalation factors for chronic exposure to benz ene and several other important highexposure HAPs and provided another comparison table showing t he differences between EPA’s reference concentrations and California EPA’s values publ ished in June 2014. The commenter also pointed out that the acute reference value used to evaluate benzene exposure is two orders of magnitude too high, leading to a very significant underestim ate of the acute non-cancer health hazards of benzene emissions from aerospace facilities.

Response: EPA’s chemical-specific toxicity values are derived using r isk assessment guidelines and approaches that are well established and vetted through the scientific community, and follow rigorous peer review processes. 36 The RTR program gives preference to EPA values for use in

36 Integrated Risk Information System (IRIS). IRIS Guida nce documents available at http://www.epa.gov/iris/backgrd.html35

risk assessments and uses other values, as appropriate, w hen those values are derived with methods and peer review processes consistent with those f ollowed by the EPA. The approach for selecting appropriate toxicity values for use in the RTR P rogram has been endorsed by the

SAB. 37

The commenter recommended that EPA use California OEHHA ’s new toxicity values for several chemicals and provided some references for the approaches used to derive those values. EPA scientists reviewed the information provided by the commente r and concluded that further

information is needed to evaluate the scientific basis and rationale for the recent changes in California OEHHA risk assessment methods. As previously e xplained, only one set of acute reference values from California OEHHA are most appropri ately designed for use in the RTR Program: the acute Reference Exposure Levels (RELs), whi ch are developed for their Air Toxics Hot Spots program – a program similar in scope and context to the RTR assessments of risk. The EPA will work on gathering the necessary information to conduct an evaluation of the scientific merit and the appropriateness of the use of California OE HHA’s new toxicity values in the context of the RTR program. Therefore, EPA did not use th e new California OEHHA toxicity values and continued to follow the SAB-endorsed approach to select the most appropriate toxicity values for this rule making.



### 6.0 Technology Review

Comment: One commenter (0830-0028) stated that EPA’s conclusion of n o new developments in practices, processes, and control technologies that w arrant revisions of the standard is correct and are appropriately supported by a review of current technol ogy and limits in EPA’s RACT/BACT/LAER Clearinghouse and MACT standards for other source categories.

The commenter noted that even if EPA were to re-review technologies rejected during the initial rulemaking, the Agency would reach similar conclusions to not adopt them today, as these control options are limited to unique operations in the in dustry, are not cost-effective, and result in the creation of other pollutants.

The commenter agreed that there are no demonstrations of add-on controls to control organic HAP emissions from the coating of assembled aerospace ve hicles, and further noted that a recent BACT analysis showed that add-on controls are not cost -effective for large aerospace components. The commenter recommended that EPA should f inalize that there are no revisions needed to the standards for primers, topcoats, depainting, ch emical milling maskants, cleaning, and waste handling operations.

Response: The EPA acknowledges the commenter’s agreement with t he results of EPA’s technology review and the conclusion that there are no new developments in practices, processes, and control technologies for primers, topcoats , depainting, chemical milling maskants, cleaning, and waste handling operations.

Comment: One commenter (0830-0030) argued that EPA may not exempt wast e handling and storage operations from the technology review because do ing so would violate CAA §

37 http://www.epa.gov/ttn/atw/nata1999/99pdfs/healtheffectsinfo.pdf36

7412(d)(6) and disagreed with EPA’s basis for not doing a techn ology review in the current rulemaking.

First, the commenter argued that the Act requires a revi ew of the existing emission standards at least every 8 years after promulgation, including reviewing de velopments in practices, processes, and control technologies. 38 The commenter added that EPA argued that “there is no n eed to do a technology review” in the current rulemaking 39 because EPA sets standards for wastes not covered by RCRA and EPA stated that “[t]he practical effect of [this rule] is that all HAPcontaining wastes generated by aerospace manufacturing and rew ork operations are subject to RCRA and are exempt from the requirements of 40 CFR 63.748.” 40 The commenter added that in 1994, for waste that are not subject to the provisions of RCRA, the agency promulgated standards that required HAP-containing waste to be handled i n such a manner that spills are minimized for waste handling and storage operations. 41 The commenter added that EPA recognizes that it must perform the first required 8-year review of the 1994 standards. 42

In addition, the commenter argued that EPA has not provided any data or other evidence showing that all aerospace waste is exempt from the curr ent standards that apply to aerospace facilities nor has it shown that aerospace waste and storage handling is actually regulated by

RCRA. The commenter stated that EPA cites no RCRA re gulations that regulate the emissions of these operations, including their hazardous air emissions, much less any such regulations that do so effectively. The commenter argued that unless EPA can show that all aerospace waste storage and handling operations’ air emissions are appropriately r egulated by RCRA, at least as stringently as CAA § 112(d) and (f) require, then its refus al to review these standards is arbitrary and capricious.

The commenter argued that EPA’s stated reason for origi nally exempting certain waste (that is subject to RCRA) from the Clean Air Act waste handling a nd storage standards conflicts with and does not support a refusal to do a CAA § 112(d)(6) review now. The commenter noted that EPA states in the current rule preamble that it promulgat ed the original exemption to try to avoid creating “potential conflicts” with RCRA. 43 However, the commenter argued that the agency’s explanation for the original exemption was actually mo re nuanced as EPA stated that it was promulgating the exemption “so that the ... standards would n ot require less strict handling and storage of waste than the RCRA requirements.” 44 The commenter argued that there is no indication that it would create “potential conflicts” for EPA to review the existing CAA standards to see if there are “developments” that it sh ould account for in revised standards, as the CAA requires, to assure stronger standards than currently apply under either CAA or RCRA. The commenter explained that it would be fully consistent wit h the originally stated objective of assuring sufficiently strict requirements for EPA to perfo rm the requisite review now and would

allow EPA to assess and determine whether the CAA stan dards are up to date and sufficiently stringent. The commenter added that if EPA performs the requisite CAA review and finds that

38 42 U.S.C. § 7412(d)(6).

39 80 Fed. Reg. at 8419 ( citing 59 Fed. Reg. 29,216).

40 Id.

41 Id. ( citing 40 CFR 63.748).

42 Id. at 8395; Consent Decree, Sierra Club v. Jackson , Case No. 09-cv-00152-SBA (N.D. Cal. Sept. 26, 2011).

43 80 Fed. Reg. at 8419.

44 1994 Proposed Rule, 59 Fed. Reg. at 29,223 (emphasis added).37

there are “developments” in waste storage and handling, EP A will then need to revise the standards to assure that they satisfy CAA § 112(d), including § 112(d)(2) and (3). As part of this analysis, EPA can ensure the standards are not less stri ngent than what is required under RCRA, and thus avoid any potential conflicts, according to the com menter.

The commenter argued that the reviews required by CAA § 7412(d)( 6) and (f)(2) are both necessary in part to assure that there are appropriate emission standards in place for hazardous air pollutants emitted by aerospace waste storage and handl ing operations. The commenter stated that EPA has no authority to exempt major sources from CAA § 7412 standards. The commenter noted that EPA acknowledged that it also may not set no c ontrol standards. 45 The commenter added that these must meet a particular stringency test as defined by CAA § 7412(d)(2) and (3). The commenter argued that EPA may not evade these CAA r esponsibilities by referring to a different statute (i.e., RCRA) that does not include an d cannot substitute for the § 7412 requirements. The commenter argued that EPA must ensure that the required CAA § 7412(d)(6) review is satisfied and that any HAPs emitted from waste storage and handling operations are subject to CAA § 7412(d) standards that assure the “maximum achie vable” degree of emission

reductions.

The commenter noted that it is unclear whether EPA incl uded waste handling and storage operations in its CAA § 7412(f)(2) risk assessment. The com menter argued that EPA did not state whether it included emissions from waste storage an d handling operations in the CAA § 7412(f)(2) review which requires assessing risks to public heal th and the environment under the existing standards.

Finally, the commenter argued that EPA may not rely on the original exemption for certain waste operations because that, in turn, is unlawful under CAA § 7412(c) and (d). Where Congress intended to allow EPA to exempt sources from CAA § 7412 standa rds based on the existence of standards under other statutes, it did so expressly, accor ding to the commenter. See, e.g., CAA § 7412(d)(9) (radionuclide emissions provision). The commenter added that there is no such exemption for aerospace sources, or any part of their emi ssions.

Response: The EPA disagrees with the commenter. The complete r esponse to this comment can be found in section IV.K.3 of the preamble to the final ru le.

Comment: One commenter (0830-0028) requested that EPA clarify in the final rule that HAPcontaining solvent wipes subject to the Resource Conserva tion and Recovery Act (RCRA) requirements are exempted from waste handling requirement s of the Aerospace NESHAP. The commenter referenced recent RCRA rule changes including Conditional Exclusions from Solid Waste and Hazardous Waste for Solvent-Contaminated Wipes [78 Fed. Reg. 46448 (July 31, 2013)], and noted that although these wipes are conditionally excluded from the definition of solid waste or hazardous waste, they are subject to RCR A management and emission control requirements in order to retain the solid or hazardous was te exclusion. The commenter expressed concern that additional regulation of these wipes under t he Aerospace NESHAP may result in conflicting requirements.

45 80 Fed. Reg. at 8419.38

Response: The EPA proposed no revisions to the standards in 40 CFR 63. 748 for handling and storage of waste that would potentially affect HAP-conta ining solvent wipes. Because no issues were raised with respect to the current provisions and th e use of solvent wipes since promulgation of the original aerospace NESHAP in 1995 we se e no need to provide clarification at this time. However, the EPA has revised 40 CFR 63.741 to r emove and reserve paragraph (e), and has revised 40 CFR 63.744(a) and 63.748 to clarify the relatio nship between subpart GG and the regulations to implement RCRA (40 CFR parts 260 through 268). Under these clarifications in the final rule, solvent laden materials that are c omplying with the requirements in 40 CFR parts 262 through 268 are not subject to the requirements in 40 CFR 63.744(a) and 63.748.

Comment: One commenter (0830-0030) stated that EPA has not reviewed h ow and if the existing standards control polycyclic organic matter (POM ) or addressed whether the standards are currently adequate to do so under CAA § 7412(d) or (f) as part of the required reviews in this rulemaking. The commenter added that EPA has not addressed wh at emission standards are needed for specialty coating operations to restrict POM as required by CAA § 7412(d)(2) and (3), by assuring the maximum achievable degree of emission r eductions of POM. The commenter argued that EPA has not performed any risk asses sment for POM, which is a multipathway, persistent bioaccumulative toxic pollutant, or shown that it has satisfied CAA § 7412(f)(2) for this pollutant. 46 The commenter explained that EPA is legally required to regulate and restrict all pollutants emitted by aerospace sources. 47 Thus, EPA’s failure to assess health risks from POM violates CAA § 7412(f)(2), and EPA’s failure t o address and limit POM emissions from specialty coating operations also violat es CAA § 7412(d), including CAA § 7412(d)(2), (d)(3), and (d)(6).

Response: The EPA disagrees with the commenter. As explained at proposal and in the preamble to the final rule, the EPA has completed a tec hnology review and risk assessment for surface coatings operations of the Aerospace Manufacturin g and Rework facilities source category, under CAA sections 112(d)(6) and (f)(2), respectively . Additionally, as proposed, EPA is finalizing MACT standards for the specialty coating sub category, under CAA section 112(d)(3). POM is an organic HAP and the EPA established a tota l organic HAP standard for primer, topcoat, and chemical milling maskant operations in subpart GG promulgated in 1995 (60 FR 45956, September 1, 1995). The primary source of POM is fo rmation during fossil fuel combustion, and in the production of coke, asphalt, and co al tar. 48 The only POM compound the EPA identified from the surface coating operations is nap hthalene. This is supported by the data collected for the risk assessment using the 2011 ICR. The 2011 ICR data, which are in the EPA's risk modeling file, included emissions of POM from non-surf ace coating operations at only two facilities and from surface coating operations at 23 faci lities. As stated previously, the POM from surface coating operations is naphthalene emissions from currently regulated surface coating operations and from specialty coating operations. These data for naphthalene were included in the risk assessment for the surface coating operations. No other forms of POM were reported from surface coating operations.

46 Residual Risk Assessment for Aerospace, EPA-HQ-OAR-2014-0830 -0004 (does not include POM risk review).

47 42 U.S.C. § 7412(d); Nat’l Lime Assn. , 233 F.3d at 633.

48 http://www3.epa.gov/airtoxics/hlthef/polycycl.html39

The MACT standards applicable to certain subcategories i n the aerospace surface coating source category are in place to control HAP emissions, includ ing naphthalene (40 CFR Part 63, Subpart GG). In our February 2015 proposal, we explained that EPA h ad originally set a MACT floor of “no control” for specialty coatings in subpart GG whe n first promulgated in 1995, which is not

allowed under Sierra Club v. EPA , 479 F.3d 875 (D.C. Cir. 2007). We therefore proposed revisions that would set limits for specialty coatings ( 80 FR 8399, February 17, 2015). In the final rulemaking EPA is promulgating a total organic HAP st andard for specialty coating operations similar to the other subcategories for this s ource category. A reduction in total organic HAP includes a reduction in the naphthalene emitted from aerospace coating operations.

The EPA also disagrees with the commenter’s statement that the EPA has not reviewed how and if the existing standards control POM and whether they ar e adequate to control POM or whether the proposed specialty coating standards are sufficient t o address POM emissions. As previously explained, the EPA performed both a risk assessment and te chnology review for the Aerospace Manufacturing and Rework facilities source category. As a lso previously explained, under the CAA Section 112(d)(6) technology review, we must review th e technology-based standards and revise them “as necessary (taking into account developm ents in practices, processes, and control technologies)” no less frequently than every 8 years. ” As part of the technology review of the aerospace MACT standards, EPA found that surface coating o perations can be controlled through coating reformulation, and emissions can also b e captured using hoods, spray booths, and ventilation systems which can then route captured pollutants to control devices like thermal oxidizers. The standards for primer, topcoat, chemical m illing maskant, and specialty coating operations, in fact, include multiple ways to control o rganic HAP emissions, such as

reformulation and add-on controls or a combination of th e two. However, as with most surface coating operations, the predominant strategy for meeting the standards remains reformulation because the surface coating operations are typically pe rformed manually by painters in conditions that create large air flow rates and low po llutant concentrations. Add-on controls are not cost effective in these situations with large air flows and low pollutant concentrations. Addon control devices are typically seen at sources using e ither robotic surface coating operations or when the surface coating operations are vented with othe r HAP-emitting processes to provide a

concentrated emissions stream.

As also explained earlier, as part of the CAA section 112(f)(2) residual risk review, the EPA developed a risk modeling file. As noted above, two faciliti es reported emissions of POM from non-surface coating operations and these emissions were included in the risk assessment on the basis of whole-facility emissions. Naphthalene emissi ons were reported from surface coating operations at 23 facilities, including currently regulated s urface coating operations and from specialty coating operations. These data for naphthalene were included in the risk assessment for the surface coating operations. No other forms of POM w ere reported from surface coating operations. For further information on the risk assessm ent approach, see the Residual Risk Assessment for the Aerospace Manufacturing and Rework Fa cilities Source Category in Support of the January, 2015 Risk and Technology Review Proposal, J anuary 2015, which is available in

the docket for this action.

The EPA also compared the 1990 naphthalene baseline emissi on inventory for the aerospace industry (79 FR 74661, December 16, 2014) to the more recent naphthal ene emissions from the risk modeling file. When the aerospace manufacturing and rew ork facilities MACT standard was40

promulgated, the anticipated emission reductions from surfa ce coating operations was 59 percent (60 FR 45952, September 1, 1995). From this comparative analysis between the 1990 baseline inventory and the risk modeling file, we found that emissions of total naphthalene for all manufacturing and rework operations in the aerospace sourc e category have been reduced by 99.96 percent since the updated 1990 baseline inventory. The result s show that the MACT standards for aerospace coating operation, including the l imits for total organic HAP, have resulted in naphthalene reductions of a magnitude that is typically associated only with the use of

add-on controls. This result also demonstrates that the current approach of regulating total organic HAP and providing the option of using add-on controls a re adequate to address naphthalene emissions under CAA § 7412(d) and (f). In additio n, the current RTR modeling file, which has been updated with the latest available informati on, shows no POM emissions other than naphthalene from aerospace surface coating operatio ns.

As noted above, POM is an organic compound with more than one benzene ring and a boiling point greater than or equal to 100 degrees Celsius. As explaine d at proposal, we conducted a multipathway screening analysis of seven PB-HAP, which i ncluded POM. (80 FR 8403-06, 8410; February 17, 2015). We also explained that this screening ana lysis indicated that PB-HAP emissions from this source category did not exceed the s creening emissions rates for any of the compounds we had evaluated. (80 FR 8415). We did not receive any comments disagreeing with either these results or our conclusion. This multipa thway risk analysis did not consider naphthalene because naphthalene, unlike the other POM che micals modeled in the multipathway analysis, is short-lived in environmental media due to it s tendency to volatilize and biodegrade and, consequently, will not build up in environmental media o ver time. 49 It has a moderate affinity for lipids and will undergo short-term bioaccu mulation in tissues; however, biochemical processes lead to its biodegradation and elimination. We bel ieve that its inclusion would have resulted in less accurate and less meaningful estimates of media concentrations and multipathway risk.



### 7.0 Proposed Regulation of Specialty Coatings

7.1 Legal Basis to Regulate Specialty Coatings

Comment: One commenter (0830-0030) agreed with the EPA that the prop osed regulation of specialty coatings is legally required, but argued that the proposed standards themselves are too weak. The commenter noted that EPA acknowledged that it m ay not leave unregulated any hazardous air pollutants emitted by these sources, or set a “no control” standard. 50 The commenter agreed that while setting organic HAP standards f or specialty coating operations that follow the Control Techniques Guidelines (“CTG”) 51 for VOCs and applying the existing 10-90 percent efficiency requirements applicable to other opera tions to control metals and inorganic

50 Nat’l Lime Assn., 233 F.3d at 633-34 (D.C. Cir. 2000); Sier ra Club v. EPA, 479 F.3d at 878, 883.

51 EPA, Guideline Series, Control of Volatile Organic Compound Emissions f rom Coating Operations at Aerospace Manufacturing and Rework Operations , EPA 453/R-97-004 at B-4 (Dec. 1997), EPA-HQ-OAR-2014-0830-0020.41

HAPs from specialty coating operations are improvements to the current no-control status for these sources, it is insufficient to satisfy the Act.

The commenter further argued that the EPA is required by C AA § 7412(d)(3) to use available data and set standards requiring at least the average emi ssion limitation that has been achieved by the best 12 percent of existing sources 52 and not base it on emission reductions achieved by the best 32 percent of sources (35 of the 109 facilities th at reported specialty coatings are located in ozone non-attainment areas and are likely complying with VOC limits based on the CTG). 53
The commenter added that if EPA had fulfilled this require ment, it is likely to require more than the small HAP reduction it predicts its proposed rule wou ld achieve (16 percent, or 58 of 360 tons per year).

Response: The EPA acknowledges the commenters support for the EPA ’s determination that the regulation of specialty coatings is required under CAA § 7412.

However, the EPA disagrees with the comment that the standards should be more stringent. For MACT standards, the statute specifies certain minimum stringency requirements, which are referred to as MACT floor requirements. See CAA sectio n 112(d)(3). National Lime Assn. v.

EPA , 233 F.3d 625 (D.C. Cir. 2000). For new sources, the MACT flo or cannot be less stringent than the emission control achieved in practice by the b est-controlled similar source. The MACT standards for existing sources can be less stringent than floors for new sources, but they cannot be less stringent than the average emission limitatio n achieved by the best-performing 12 percent of existing sources in the category or subcategory (or the best-performing five sources for categories or subcategories with fewer than 30 sources) . In setting MACT, CAA section 112(d)(3) requires the EPA to promulgate standards that must be at least as st ringent as the average emissions limitation achieved by the best performing 12 percent of existing sources “for which the Administrator has emissions information.” Our approach to use of av ailable data is also supported by

NRDC v. EPA , 529 F.3d 1077, 1086) (D.C. Cir. 2008). (The EPA typically has wide latitude in determining the extent of data-gathering necessary to solve a proble m.).

As the EPA explained in the preamble to the proposed rule ( 80 FR 8420), the EPA does not believe that any substantial difference exists among the state rules that are based on the CTG that

would be the basis for EPA’s calculation of the MACT f loor. Therefore, the 35 facilities located in ozone non-attainment areas represent the best perfo rmers, and therefore fulfill the CAA’s requirement to determine the MACT floor based on the aver age emission limitation achieved by the top 12 percent of sources. Furthermore, the EPA beli eves that those 35 facilities subject to state rules are all complying with essentially equivalen t emission limitations for purposes of setting emission limitations under CAA section 112(d)(3). The EPA would not reach a different determination of MACT for specialty coatings if the EPA looked at a smaller subset of facilities

than the 35 that are in ozone non-attainment areas and subject to specialty coating limits based

on the CTG.

The EPA's approach for the determination of the MACT fl oor and the results of the MACT analysis, including the analysis of options beyond the MA CT floor, are documented in the memorandum, Determination of Maximum Achievable Control T echnology (MACT) for

52 42 U.S.C. § 7412(d)(3).

53 80 Fed. Reg. at 8420.42

Specialty Coating Operations in the Aerospace Manufacturi ng and Rework Facilities Source Category, that is found in the docket for this rule making. As documented in that memorandum, the EPA determined that MACT was equivalent to the MACT f loor for both organic HAP and inorganic HAP, and the EPA identified no control option s that were more stringent than the MACT floors for organic and inorganic HAP.

Comment: One commenter (0830-0028) noted that the EPA's risk modeling ha s shown that specialty coatings account for less than 2 percent of th e risk from the facility with the highest modeled risk, and the maximum cancer risk from specialty co atings is less than 1-in-1 million at over 90 percent of facilities and less than 10-in-1 millio n at all facilities. As a result, specialty coatings do not warrant regulation based on risk.

The commenter argued that in light of the fact that th e current standards are already protective with an ample margin of safety, the EPA should not regul ate specialty coatings. The commenter argued that using EPA's $590,000 per year cost estimate, the cost of regulation would be equivalent to $67 million to avoid a single additional expec ted cancer case.

The commenter argued that EPA is not compelled to regulate specialty coatings, based on EPA decisions to not regulate other unregulated sources in other source categories during the RTR process. The commenter argued that specialty coatings shou ld not be regulated because of their specialized functions and the limited quantities in which t hey are used, similar to the reasons they were not regulated in the 1995 NESHAP or subsequent amen dments.

The commenter argued that EPA should not regulate specialt y coating operations or at least defer such regulation until such time that costs would be reason able and EPA can be certain that critical specialty coatings will not be eliminated with out a qualified replacement. The commenter stated that the decision to regulate these operations at this time is discretionary because the risk is acceptable (because there have been no advances in techno logy) and no one challenged EPA’s decision not to regulate them in the original rule or i n previous amendments to subpart GG. The commenter further stated that proceeding to regulate, given the potential costs and impacts on the industry, would be inconsistent with EPA’s obligations to enga ge in reasoned decision-making and would be arbitrary, capricious, and an abuse of discret ion.

The commenter argued that EPA is not required to correct a ny perceived deficiencies found in a MACT during a CAA Section 112(d)(6) review, rather EPA’s only obligation in this rulemaking is to satisfy the requirements of CAA Section 112(d)(6) an d (f), similar to EPA’s decision for the Pulp and Paper NESHAP. 54 The commenter further noted that even if EPA decided th at it should have regulated specialty coating operations, EPA should de cline to do so since it is not required to correct any deficiency in an underlying MACT standard when conducting the technology review. The commenter stated that this approach would be co nsistent with recently-upheld EPA decisions to decline to conduct rulemaking for greenhouse gas em issions from coal mines. 55

54 EPA, N ational Emission Standards for Hazardous Air Pollutants from the Pulp and Paper Industry (40 CFR Part 63, Subpart S) Residual Risk and Technology Review, Final Amendments Res ponse to Public Comments on December 27, 2011 Proposal, at 107 (July 2012) (Pulp and Paper RTC).

55 WildEarth Guardians v. EPA , 751 F.3d 649 (D.C. Cir. 2014).43

The commenter argued, finally, that recent case preceden t regarding uncontrolled sources 56 does not compel EPA to revise longstanding regulatory exclusio ns that are justified by legitimate de

minimis principles and that were never previously challenged by any party particularly when there will not be a meaningful benefit to the public heal th from such regulation and the cost of regulating will be high.

Response: The EPA is finalizing standards to address organic and inorgani c HAP emissions from specialty coating operations, which are currently un regulated emission sources, under CAA 112(d)(2) and (d)(3). The EPA is not, however, promulgating t hese standards as part of its 112(d)(6) technology review. The EPA disagrees that correct ing problems with existing MACT standards is a necessary part of a 112(d)(6) technology revi ew. We also disagree with the comment that CAA section 112(d)(6) is the EPA’s sole auth ority for revising existing MACT standards. As a general matter, an agency remains free t o revise improperly promulgated or otherwise unsupportable rules, even in the absence of a r emand from a Court. United Gas Improvement Co. v. Callery Props. Inc. , 382 U.S. 223, 229 (1996) (An agency, like a court, can undo what is wrongfully done by virtues of its order.”). A s explained in earlier responses in this response to comment document, we believe that CAA sect ion 112 does not expressly address this issue, and the EPA has discretion in determining ho w to address improperly promulgated floor determinations. CAA section 112(d)(6) provides that the agency must review and revise “as necessary.” The “as necessary” language must be read in the context of the provision, which focuses on the review of developments that have occurred since the time of the original promulgation of the MACT standard and thus, should not be read as a mandate to correct flaws that existed at the time of the original promulgation. Fur ther, we believe that Portland Cement

Assn. v. EPA , 665 F.3d 177, 189 (D.C. Cir. 2011) confirms that EPA is not cons trained by CAA section 112(d)(6) and may reassess its standards more often , including revising existing floors if

need be. We also note that the D.C. Circuit also hel d that EPA may permissibly amend improper MACT determinations, including amendments to improperly pro mulgated floor determinations, using its authority under CAA sections 112(d) (2) and (3). Id . Thus, we believe that we may amend improper MACT determinations, including amendments to i mproperly promulgated floor determinations, under sections 112(d) (2) and (3). Medical Waste Institute v. EPA , 645 F.3d 420, 425-27 (D.C. Cir. 2011) (resetting MACT floor, based on post-co mpliance data, permissible when originally-established floor was improperly establishe d, and permissibility of the EPA’s action does not turn on whether the prior standard was r emanded or vacated). The commenter is, thus, incorrect that CAA section 112(d)(6) provides the excl usive authority to address HAP emissions from specialty coatings here. Put another wa y, if the EPA did not adopt a proper MACT standard initially, it is not amending a MACT standa rd but adopting one for the first time. Here, the EPA adopted no MACT standard at all fo r these HAP, an approach soundly rejected by the D.C. Circuit in National Lime , 233 F.3d at 633-34.

We also disagree with the comment that the EPA is no t mandated to regulate de minimis HAP.

While the EPA’s de minimis authority exists to help avoid what might be perceived as excessive regulation of tiny amounts of pollutants, it is unavail able “where the regulatory function does provide benefits, in the sense of furthering the regulatory objectives, but the agency concludes that the acknowledged benefits are exceeded by the costs.” Alabama Power v. EPA , 636 F.2d 323, 360-61 &n.89 (D.C. Cir. 1979). According a de minimis exemption to CAA sections

56 UARG v. EPA , 134 S. Ct. 2427, 2449 (2014)44

112(d)(2) and (3) are unavailable because it would frustrate a primary legislative goal by carving out tons of HAP emissions from regulation. Moreover, the EPA’s rejection of the de minimis concept has been affirmed by the U.S. Court of Appeals f or the D.C. Circuit in National Lime

Assn. v. EPA , 233 F.3d 625, 640 (D.C. Cir. 2000), where the court rejected the petitioner’s claim that in light of both high costs and low quantities of H AP at issue in that rule, the EPA should

read a de minimis exemption into the requirement to regulate all HAP emitte d by major sources. The Court found that “EPA reasonably rejected this argumen t on the ground that the statute ‘does not provide for exception from emissions standards ba sed on de minimis principles where a

MACT floor exists.’” National Lime Assn. , at 640. We also continue to believe that CAA section 112 is replete with careful definitions of volume or e ffect based limitations on regulation, indicating that Congress has already defined what amounts o f HAP emissions are too small to warrant MACT standards. The requirement to adopt MACT em ission limitations, for example, applies without exception to “category or subcategory of major sources . . . of [HAP].” CAA section 112(d)(1). For sources below the major sources thr eshold, however, EPA has discretion to require “generally available control technologies or management practices.” CAA section 112(d)(5). Congress has thus defined volumetrically which sourc es’ emissions are small enough not to warrant mandatory MACT standards.

The EPA also disagrees with the commenter’s interpreta tion of EPA’s response to the question of establishing standards for unregulated sources in a commen t on the proposed RTR for the Pulp and Paper NESHAP. In the pulp and paper response, the EP A was, as the commenter correctly noted, arguing only that the EPA is not required to establish standards for previously unregulated sources under CAA section 112(d)(6) as explained abo ve. However, there is nothing in EPA’s pulp and paper response to support the commenter’s argument that the EPA is not required to regulate specialty coatings under CAA 112(d)(2) and ( d)(3). In fact, in the same EPA response cited by the commenter, the EPA states that, “We intend to further investigate potentially deficient standards and plan to address them i n a future sector rule proposed under section 112(d)(2) and (3).”

The Supreme Court case cited by the commenter, UARG v. EPA , is not relevant to the decision to regulate HAP from specialty coatings because it dealt with the question of whether sources should be required to determine BACT for greenhouse gas emis sions as part of the new source review permitting process. It did not deal with the regulati on of HAP and the determination of

MACT under CAA section 112.

Comment: One commenter (0830-0026) argued that the EPA is not compel led to regulate specialty coatings under CAA Section 112(d)(2) and (3) by the "Brick MACT" decision. 57 The commenter argued that the situation in the Aerospace NES HAP is different from the situation in the Brick MACT case. According to the commenter, the E PA erred in the Brick MACT case "by failing to regulate processes that emitted HAP, in some i nstances by establishing a MACT floor

of 'no control.'" 58 The commenter argued that in the Aerospace NESHAP, in contrast, the EPA did not establish a MACT floor of “no control,” but i nstead excluded specialty coatings from that MACT floor because the amount of organic HAP emissions generated by coating-related

57 Sierra Club v. EPA , 479 F.3d 875 (D.C. Cir. 2007).

58 Id . at 8399.45

operations is “relatively small,” the coatings are highl y specialized, and subcategorization for specialty coatings “can be significant,” “resulting in lower potential emission reductions.” 59 The commenter argued that the exclusion for specialty coati ngs is lawful under the Brick MACT decision, and that if EPA’s interpretation was taken to its logical conclusion, it would be unlawful for the Agency to exempt any subcategory of sourc e from any MACT standard, and this is a result that is not mandated by the Brick MACT decision.

Response: The EPA disagrees with the commenter’s interpretatio n of the “Brick MACT” decision relative to the regulation of specialty coatin gs. The EPA's complete response to this comment can be found in section IV.C.3 in the preamble to the final rule amendments.

7.2 Determination of Specialty Coating Limits and Definitions

Comment: Two commenters (0830-0027, 0830-0028) agreed that, if the EPA decides to regulate specialty coatings, the Aerospace CTG limits are the most appropriate basis for determining the floor and represent MACT.

One commenter (0830-0027) agreed that the EPA correctly bas ed the MACT floor analysis on

the CTG limits as the basis for a national rule bec ause more stringent limits that were identified were developed for areas with specific climate conditio ns. The commenter noted that the more stringent limits also rely on alternative compliance m echanisms, such as exemptions and variances, which were not included in the CTG and were n ot proposed for the Aerospace

NESHAP.

Another commenter (0830-0028) argued that the EPA’s decision to rely on the use of the CTG’s VOC limits for MACT was justified because the data co llected by the 2008 ICR was insufficient for determining MACT. The commenter argued that the ICR di d not collect the data that would be necessary to classify similar sources so that the top performing operations in each

classification could be identified. This information would have included: detailed information on the coatings and specifications to determine whether the c oating operations in which they are used are similar; data on coatings that may be used in several specialty coating classifications; and data on all specialty coatings used over several year s. The commenter cited, as an example, the category of “nonstructural adhesives” and noted that even within this category there are

numerous different adhesive formulations for different substrates and different performance requirements that result in different HAP contents. T he ICR did not collect sufficient information to differentiate these applications for different HAP co ntents. The commenter also noted that the ICR did not collect information to identify specialty co atings that are used across multiple coating categories, because the ICR asked users to choose a single classification for each coating.

The commenter agreed with and supported the EPA’s determinat ion that the VOC limits developed under the CTG represent the MACT because these limits represent the emission levels achieved by the top 12 percent of sources. The commenter note d that the courts have determined that emission limits may be used to provide a reasonable estimate of the performance of the best

59 59 Fed. Reg. 29,216, 29,239 (June 6, 1994).46

performing facilities. 60 The commenter also noted that the limits-based approach was supported by the D.C. Circuit in Mossville Environmental Action Now v. EPA , where the court found that EPA met the burden of supporting the use of regulatory limits in setting a MACT floor when the Agency “cited the great variability of emission levels, even within the same plants, and the inherent difficulty in other standards it considered.” 61

The same commenter also argued that the fact that no s tate or regional specialty limits are more stringent than the CTG limits supports the EPA’s determi nation that the CTG limits can be used to reasonably estimate the performance of the best perf orming facilities. The commenter argued that although some states and regions have adopted limits for certain types of specialty coating operations that differ from the CTG limits, the state and regional rules are not more stringent because these rules typically provide different exemptio ns, different definitions to classify specialty coatings, or additional classes or subclasses with VOC limits different than the CTG. The commenter also argued that the EPA also does not ha ve sufficient data to determine whether any of the more stringent limits are actually being achi eved in practice.

The commenter also argued that the determination that RA CT limits from a CTG also represent MACT is not unique, and cited examples from the Shipbuildi ng and Repair Surface Coating NESHAP (subpart II), and the Miscellaneous Metal Parts a nd Products Surface Coating NESHAP (subpart MMMM). Finally, the commenter argued that the legislative history of the

CAA 62 and the language of section 183(b)(3), which directs the EPA directs EPA to “take into account the applicable requirements” of section 112 when de veloping the CTG, support the overall concept of harmonizing the NESHAP limits with the CTG limits.

The same commenter also argued that the EPA’s decision to use an alternative approach for determining MACT was justified by the diversity of special ty coating operations and formulations needed by those operations. The commenter noted that the determination of MACT for new and existing sources according to CAA section 112 is b ased on the comparison of performance among similar sources for which the EPA has data. The commenter argued that given the diversity of specialty coating operations in the aerospace industry, and the number of different coating categories and formulations, and the sa fety considerations needed, it would be difficult and impractical to identify and classify simi lar sources to conduct a straightforward determination of MACT floors. The commenter argued that taking all of these factors into account to create homogenous grouping of similar sources coul d lead to the creation of hundreds of classifications, many of which would be likely to hav e only a single facility. Thus, the commenter argued, the EPA’s decision to use an alternativ e approach to determining MACT is justified.

Response: The EPA acknowledges the commenter’s support of the EPA’ s use of the CTG limits

as the basis for MACT and the determination that the C TG’s VOC limits present MACT for the control of HAP from specialty coatings. As earlier explained, CAA section 112(d)(3) requires the

60 Cement Kiln Recycling Coal. v. EPA, 255 F.3d 855, 861-62 (D.C. Cir. 2001); Sierra Club v. EPA, 167 F.3d 658, 661 (D.C. Cir. 1999).

61 370 F.3d 1232, 1242 (D.C. Cir. 2004).

62 H.R. R

EP . N O . 101-490 at 249 (1990) (Rep. accompanying on H.R. 3030) reprinted in 2 S ENATE C OMM . O N
E NV ' T A ND P UB .W ORKS , 103 D C ONG ., A L EGISLATIVE H ISTORY O F T HE C LEAN A IR A CT A MENDMENTS O F 1990, at 3273 (1993).47

EPA to promulgate standards that must be at least as stringent as the average emissions limitation achieved by the best performing 12 percent of existing sources “for which t he Administrator has emissions information.” Our approach to use of available data is al so supported by NRDC v. EPA

, 529 F.3d 1077, 1086) (D.C. Cir. 2008). (The EPA typically has wide latitude in determining the extent of data-gathering necessary to solve a problem.).

Comment: One commenter (0830-0030) argued that the EPA cannot propose to apply the existing source requirement to new sources. The commenter added that CAA § 7412(d)(3) requires EPA to match the emission limitation achieve d by the single best-performing source but EPA has not addressed or met this requirement.

The same commenter also argued that for all sources, EP A must perform the requisite beyondthe-floor analysis to consider setting standards that ar e more stringent than the floor and, ultimately, must require the “maximum achievable” degree of emission reduction from all sources, as required by CAA § 7412(d)(2). The commenter argued that EPA has not performed the required beyond-the-floor analysis for specialty coa ting operations. The commenter argued that for this type of source – where EPA is requiring only 58 tons per year of reductions, of a total of 360 tons per year it knows are emitted – it is hig hly likely that a beyond-the-floor analysis will show significant additional reductions are achievable.

Response: Congress specified in CAA section 112(d)(3) the minimum level of emiss ion reduction that could satisfy the requirement to adopt MACT. For new sourc es, MACT “shall not be less stringent than the emission control that is achieved in practice by t he best controlled similar source.” For existing sources, MACT standards must be at least as stringent as the average emissions limitation achieved by the best performing 12 percent of existing sources ( for which the Administrator has emissions information) or the best performi ng 5 sources for source categories with less than 30 sources. Thus, CAA section 112(d) requires the EPA to establis h the MACT floor for new sources differently than for existing sources. But the EPA is prohibited from adopting the same standard for new sources as for existing sources only where the ava ilable data indicate that the emission control that is achieved in practice by the best controlled s imilar source is in fact more stringent than the standards set for existing sources. As the EPA explained in the MACT memo for specialty coatings 63 and in the preamble to the proposed rule 64 the EPA did identify some cases

in which facilities are in locations with different VOC limits than in the CTG. However, the EPA also determined that those limits could not be compared dir ectly to the CTG limits because of different applicability criteria and additional VOC lim its for related specialty categories (i.e., in some cases where the CTG limit applied to one type of coating, the state rule would have limits for two sub-types of the coating). In addition, the EPA could not confirm whether any facilities

located in areas with these different limits were ac tually performing specialty coating operations subject to limits that were lower than in the CTG. As a result, the EPA also could not determine

whether new source MACT could be based on those lower VOC limits for all new sources or for a readily identified subcategory of new sources for both t he MACT floor analysis and for a beyond-the-floor analysis. Therefore, the CTG limits that were the basis for the MACT for existing sources was also the MACT for new sources.

63 EPA docket item EPA-HQ-OAR-2014-0830-0012.

64 80 FR 8420 – 8421.48

Similarly, as part of the beyond-the-floor MACT analy sis, the EPA identified some facilities that reported using add-on controls for some specialty coating ope rations. However, the use of addon controls is not widely used and the facilities using t he add-on controls did not achieve greater emission reductions than facilities using coatings meeti ng the VOC content limits, based on an analysis of the EPA’s ICR data. Finally, the EPA sea rched the EPA’s RACT/BACT/LAER Clearinghouse, and the California Statewide Best Availa ble Control Technology (BACT) Clearinghouse, and found no cases in which add-on controls were determined to be BACT or LAER for specialty coating operations.

Comment: One commenter (0830-0028) argued that the EPA should not issue dual limits for VOC and HAP for specialty coatings, and should clarify that the VOC limits are not separately enforceable and are used only as a surrogate for HAP. The c ommenter argued that the EPA

should make clear in the final rule that:

(1) Only the organic HAP limits are enforceable;

(2) Coatings that do not contain organic HAP are not cove red by the rule; and

(3) For coatings that do not contain exempt solvents tha t are also HAP, VOC content may be used to demonstrate compliance with the organic HAP limit s as an alternative to determining organic HAP content directly.

The commenter argued that CAA section 112 does not allow fo r the setting of VOC limits, except as a surrogate for HAP content, and then only in s ituations in which the HAP content could not exceed the VOC content. Therefore, the use of the VOC content to demonstrate compliance with the HAP content limits can only apply when the coating does not contain any exempt solvents that are HAP. The commenter argued tha t the VOC content would effectively cap the HAP content in those coatings with no exempt solvents.

The commenter also argued that under either approach, coati ngs that do not contain any organic HAP cannot be subject to the HAP content limits or the VOC limits as a surrogate for HAP, and the rule should include a provision to clarify this. The c ommenter argued that facilities can use coating formulation information to establish whether or not the coatings contain organic HAP.

Response: The EPA agrees with the commenter’s recommendations to clarify the relationship between the VOC content of coatings and the HAP emiss ion limits. The EPA's complete response to this comment can be found in section IV.D.3 in the preamble to the final rule

amendments.

Comment: One commenter (0830-0030) argued that EPA’s VOC-based limit for organic HAPs is flawed because EPA is proposing to use VOCs generally as a surrogate for HAP content limits from specialty coatings without meeting the required test to use a surrogate instead of direct HAP regulation. The commenter disagreed with EPA’s sta tement that “there is a positive correlation: between the average volatile contents o f the coating categories and the CTG VOC limits, between the average HAP contents per category and the CTG VOC limits, and between the average HAP contents and the average volatile cont ents per category.” The commenter argued that this conclusory statement is arbitrary and capr icious because it does not explain how49

EPA believes this is true. The commenter added that it i s also unlawful and arbitrary because EPA has not met the legal test to use a pollutant like VOCs as a surrogate for a HAP.

The commenter pointed out that the D.C. Circuit has re cognized that EPA must justify the use of a surrogate based on facts in the record that show surroga te regulation will assure proper control

of the listed HAPs themselves. The commenter added that EPA has neither attempted to meet nor has it met the test to use a single pollutant to contro l other emitted hazardous air pollutants, as it is legally required to do. The commenter argued that a surr ogate is reasonable only if it meets three conditions: (1) the target pollutant(s) must invaria bly be present in the surrogate; (2) the control technology used to control the surrogate must ind iscriminately capture both the surrogate and the target pollutant(s); and (3) control of the surro gate must be “the only means by which facilities achieve reductions in the target pollutant.” The commenter added that the EPA has not shown that coating content correlations between VOCs and organic HAPs (even assuming those exist) would also translate into actual emissions contro l correlation between these pollutants, or do so at a close enough rate to allow use of VOCs as a surr ogate. According to the commenter, EPA has not shown that control of VOCs is “the only m eans by which facilities achieve reductions in the target [HAP]” and must directly regulate these HAPs or meet the surrogate test.

Response: The EPA disagrees with the commenter that the EPA h as failed to meet the requirements set out in National Lime Assn., 233 F.3d at 639, on the use of VOC as a surrogate for demonstrating compliance with the limits for organic HAP for the following reasons:

1. The target pollutant(s) must invariably be present in the surrogate: all HAP are also VOC, with the exception of three chlorinated-organic HAP that are excluded from the definition of VOC because they are minimally photochemically reacti ve. These three HAP are not commonly used as solvents in specialty coatings, and for those coatings that contain those HAP, sources cannot use the VOC content to demonstrate c ompliance with the HAP content

limits.

2. The control technology used to control the surrogate must indiscriminately capture both the surrogate and the target pollutant(s): The EPA is settin g the same limit for VOC and organic HAP so that the organic HAP content cannot exceed the VOC limit, even if the coating contains organic HAP that are exempt from the definition of VOC. In the case of facilities that are using add-on controls to achieve compliance, VOC controls will have the same emission reduction efficiency for organic HAP.

3. Control of the surrogate must be “the only means by which facilities achieve reductions in the target pollutant:” The limits for specialty coatin gs are for organic HAP, not VOC. As the EPA explained in the MACT memo for specialty coatings 65 the only other potential source of data for the MACT analysis of specialty coatings was the limited 2011 ICR that requested coating data for 2008. ( As earlier explained, our approach to use of available data is als o supported by NRDC v. EPA , 529 F.3d 1077, 1086) (D.C. Cir. 2008). (The EPA typically has wide latitude in determining the extent of data-gathering necessar y to solve a problem.)). Therefore, we used the VOC limits in the CTG, as appli ed to organic HAP content, as a suitable alternative for the proposed organic HAP limits for specialty coatings. Because of the similarity between the CTG VOC limits and the organi c HAP limits, facilities may use

65 EPA docket item EPA-HQ-OAR-2014-0830-0012.50

the VOC content of their coatings to demonstrate compl iance with the organic HAP content limits, but they may not use the VOC content for coat ings that contain certain chlorinated organic HAP that are excluded from the definition of VOC. As we noted earlier, though, these three chlorinated-organic HAP are not commonly used as solvents in specialty coatings.

Thus, EPA disagrees with the commenter that EPA has f ailed to demonstrate that VOC is a suitable surrogate for HAP. The MACT memo, which is in the docket for this rulemaking, explained that there are positive correlations between the industry weighted-average volatile contents of the coating categories and the CTG VOC lim its, between the industry weightedaverage HAP contents per category and the CTG VOC limits, and between the industry weighted-average HAP contents and the average volatile c ontents per category.

The correlations were based on industry-weighted averages per specialty coating category because of the large number of data points in each cate gory from the ICR data. Basing the correlations on industry-weighted averages simply accoun ts for the fact that many of the reported specialty coatings are used in small quantities at numer ous facilities, but do not actually represent the bulk of the emissions from each specialty category.

It is also important to note that the HAP content value s used in the analysis were not corrected to remove water, and the volatiles content values were a lso not corrected to remove water or exempt solvents, in both cases because the ICR data di d not include water content of the coatings. It is also important to note that the data w ere screened to remove cases in which the calculated organic HAP content was greater than the cal culated volatiles content. These cases indicate a problem with the data that is likely due to the fact that HAP content may be reported as a range on coating data sheets (e.g., MSDS), and some facilities may have used the upper end of each range in calculating the total HAP content of the coatings, such that the total reported HAP content was greater than the volatiles content.

Comment: One commenter (0830-0025) representing the Department of Defe nse (DoD) commented that most of the coatings used at DoD facilit ies have military specifications that already meet the VOC limits in the CTG, so they will meet the proposed HAP and VOC content limits. However, the commenter argued that DoD will be unable to certify compliance with the HAP/VOC limits for some materials whose composition is classified as national security information. The materials have properties with speci fic, classified characteristics based on their use such as radiation-effect coating, according to the co mmenter. Disclosure of the composition of these materials would risk undermining the function of the coating or could provide sufficient

information that could be used to counter the effect of the coating, according to the commenter. The commenter requested that the proposed rule be modified t o continue to exempt materials that meet the definition of “Classified National Security I nformation.”

The commenter recommended that EPA amend 40 CFR 63.742 with a n additional definition for the term “Classified National Security Information” to re ad as follows:

Classified National Security Information means information that has been determined pursuant to this Executive Order 13526, “Classified National Secur ity Information,” December 29, 2009 or any successor order to require protection a gainst unauthorized

disclosure and is marked to indicate its classified stat us when in documentary form. The51

term “ Classified Information” is an alternative term that may be used instead of

“ Classified National Security Information”

.

The commenter also recommended that the EPA revise the definition of “ Electric or radiationeffect coating” in Appendix A to Subpart GG of Part 63 - Specialty Coating Definition to read as

follows:

Electric or radiation-effect coating - A coating or coating system engineered to interact, through absorption or reflection, with specific region s of the electromagnetic energy spectrum, such as the ultraviolet, visible, infrared, or microwave regions. Uses include, but are not limited to, lightning strike protection, electro magnetic pulse (EMP) protection, and radar avoidance. Coatings that have been designated as “ Classified National Security Information ’’ by the Department of Defense are exempt from compliance with 40 CFR 63 Subpart GG.

Response: The EPA agrees with the commenter. The EPA's complet e response to this comment can be found in section IV.D.3 in the preamble to the fina l rule amendments.

Comment: One commenter (0830-0028) argued that the current definition of electrostatic discharge and electromagnetic interference (EMI) coat ing in Appendix A of Subpart GG appears to limit the use of these coatings on aircraft radomes, but these coatings are commonly used on several parts of the non-metallic exterior portions of the aircraft to dissipate electrical charge— not just the composite radome. The commenter recomme nded that the EPA should change the definition to reflect all of the uses of coatings on a ircraft to state the following:

Electrostatic discharge and electromagnetic interfere nce (EMI) coating—A coating applied to space vehicles, missiles, aircraft radomes, an d helicopter blades aerospace vehicles or components to disperse static electricity o r reduce electromagnetic

interference.

Response: The EPA agrees with the commenter. The EPA's complet e response to this comment can be found in section IV.D.3 in the preamble to the fina l rule amendments.

Comment: One commenter (0830-0023) argued that the proposed rule is defi cient because it would effectively limit the definition of specialty coa tings to include only those coatings that fall within the categories listed in Table 1. The commenter a rgued that the list of specialty coatings included in Appendix A to subpart GG was not intended to represen t the universe of all specialty coatings, because the EPA also included the general defi nition of specialty coatings, and did not include any indication that the list in Appendix A was int ended to be exclusive. The commenter also argued that new specialty coatings could be allowed f or under the blanket exemption for specialty coatings under 40 CFR 63.741(f).

The commenter argued that now that the exemption under 40 CFR 63.741(f) has been removed, the proposal makes no provision for the development and use of new specialty coatings that are not covered by the existing categories. The commenter ar gued that because of advancements in the use of composites and other materials, it is inevita ble that new classes of specialty coatings will be developed that are required to meet FAA regulations , and airlines would then have no52

choice but to use the new specialty coatings and risk non -compliance with the Aerospace

NESHAP.

To address this situation, the commenter recommended that the EPA include a provision in the final rule that would specify how any new categories of spec ialty coatings are to be added to Table 1 and what requirements would apply in the interim whi le EPA developed final control requirements for those coatings. The commenter offer ed the following recommendations:

If a new specialty coating is required in a maintenance or repair operation and there is no existing category in proposed Table 1 that includes the new coating, the affected source could be allowed to use the specialty coating as formulated by the manufac turer, subject to the filing of a request with EPA to add the new category to Table 1 and until a de termination is made by the EPA as to the requested addition to Table 1 and corresponding HAP limit.

As a further alternative, upon filing of the above describe d request with EPA, an interim HAP limit for the new coating could be set at the highest HAP limit in Table 1 for similar types of specialty coatings. For example, if the new specialty coating is a topcoat with added functional characteristics that cause it to be in a new specialty coating category, the interim HAP limit for such new specialty topcoat would be the highest HAP conte nt allowable for any other specialty coating listed in Table 1 that also functions as a topcoat. This same approach could also apply to primers, adhesives and other “classes” of specialty coatings. The c ommenter suggested that this approach could also be facilitated by adding generic categories fo r “unlisted specialty topcoats,” “unlisted specialty primers,” “unlisted specialty adhesives,” etc. to Table 1 with a HAP level equal to that of the existing specialty coating in the same class ( e.g., topcoat, primer, adhesive, maskant, etc.) with the highest HAP limit. The generic HAP limit would then apply until EPA could formally amend Table 1 to include the new specialty coating and set a final H AP limit.

Response: The EPA disagrees with the commenter that the rule should be revise d to include provisions for coatings that do not meet the definitions of any of the e xisting specialty coating categories. As noted earlier, the Aerospace CTG that is the basis for the proposed specialty coating categories was published by the EPA in 1997, and since then numerous st ates have developed state

rules to reduce VOC emissions based on the CTG. In the EPA’s review of sta te rules based on the Aerospace CTG, the EPA did not found any rules with specialty coa ting categories that differed substantially from the categories in the CTG or in the table of specialty coatings in the proposed rule.

In the preamble to the proposed rule, the EPA specifically solicit ed comment and additional data on any changes needed to the definitions of specialty coating categories an d the proposed organic HAP and VOC limits. The EPA received comments to revise only two of the c urrent specialty coating category definitions, and received no requests to add any new specialty coating categories. Therefore, we do not even know if any new specialty coating would be used by sources in this source category. Under section 112(d)(1), EPA is required to “promulgate regulations establ ishing emissions standards for each category or subcategory of major sources ...o f listed hazardous air pollutants.” Because of the observed agreement between state VOC rules and th e Aerospace CTG, and because there were no requests to add new specialty coating categories, the E PA assumes that the current categories are sufficient to accommodate the range of coatings c urrently in use by major sources in this source category.53

Therefore, the EPA is not adopting the commenters suggestion to in clude a provision in the final rule that would specify how new categories of specialty c oatings could be added to Table 1 and what requirements would apply in the interim while EPA deve loped final control requirements for those coatings. Aerospace industry members and coating manufacturers have the ability to petition the EPA at any time to amend subpart GG through standard rule m aking procedures if that is needed to address newly developed coatings that do not fit into any of the current coating category definitions. The EPA is also required by CAA section 112(d)(6) to review a nd revise, as necessary, the promulgated emission standards for specialty coatings no less ofte n than every 8 years after promulgation.

7.3 Specialty Coating Application Equipment Requirements

Comment: Two commenters (0830-0028, 0830-0030) supported the EPA’s determination t hat the standards for specialty coating application equipment and inorganic HAP emissions should be proposed under CAA section 112(h). One commenter (0830-0028) a rgued that the 112(h) standards are justified because it may not be feasible t o have the emissions conveyed by a stack or captured by a spray booth; the application of measureme nt methodology may not be feasible (e.g., measuring the emission reductions achieved by high eff iciency coating application equipment), or the application of measurement technology (such as that for inorganic HAP from a spray booth) may not be economically feasible.

Response: The EPA acknowledges the commenters’ support.

Comment: One commenter (0830-0028) argued that the 40 CFR 63.745(f) should be revised to clarify that the proposed specialty coating application equipment requirements allow the use of any non-spray application equipment. The commenter argued that the rule allows the use of alternatives to the methods listed in 40 CFR 63.745(f)(1), but only if they are demonstrated to be equivalent to high-volume low-pressure (HVLP) spray or el ectrostatic spray, according to 40 CFR 63.750(i). The commenter argued that the rule should be r evised to allow all hand application methods and non-spray methods allowed in the California rules, and to require the equivalency demonstration only for spray application metho ds. The commenter argued that

because the rule is based on California standards as MACT , it must be amended to reflect those requirements; otherwise the EPA would need to propose a be yond the floor determination according to CAA section 112(d)(2).

The commenter recommended that the EPA add the following language to Section 63.745(f)(1) to clarify that other methods are allowed:

In addition to the methods in (f)(1)(i) through (f)(1)(ix ), specialty coatings may be applied by flow coating, web coating, coil coating, touch- up markers, marking pens, trowels, spatulas, daubers, rags, sponges, and mechanically and/or pneumatic-driven syringes.

Response: The EPA agrees with the commenter that any hand or non -spray application methods

should be allowed as a clarification of the current re quirements, which are intended to minimize emissions from the spray application of coatings. The EPA's complete response to this comment can be found in section IV.E.3 in the preamble to the fi nal rule amendments.54

Comment: One commenter (0830-0028) argued that adhesives, sealants, m askants, caulking materials, and inks are not atomized even when applied wit h spray application equipment; therefore, the application of these specialty coatin gs is not a spray-application operation and should not be subject to the high efficiency application equipment requirements. The commenter argued that the EPA should clarify that the application o f adhesives, sealants, and maskants, caulking materials, and inks are not subject to the appli cation equipment requirements by the following addition 40 CFR 63.745(f)(3):

(3) The following situations are exempt from the requirem ents of paragraph (f)(1) of this

section:

... (vii) Adhesives, sealants, maskants, caulking materials, and inks.

Response: The EPA agrees with the commenter. The EPA's complet e response to this comment can be found in section IV.E.3 in the preamble to the fi nal rule amendments.

Comment: One commenter (0830-0028) argued that 40 CFR 63.745(f)(3)(ii), which is an exemption from the high-efficiency application requirem ent in 40 CFR 63.745(f)(1), should be revised for two specific cases to remove the requirement for permitting agency approval. In the first, the commenter argued that in the California Sout h Coast AQMD and Antelope Valley AQMD aerospace rules on which MACT is based, there is an exemption for coatings that contain less than 20 grams of VOC per liter of coating. 66 The commenter argued that this exemption accommodates spray application of low VOC coatings wit h high solid contents that are not practical to apply with high-efficiency equipment, such a s high solid/low VOC ceramic coatings applied to reduce the infrared signature of military aircraft are classified as electric or radiationeffect specialty coatings. These coatings are not water -reducible and, due to high viscosity, cannot be spray applied using high-efficiency application equ ipment, according to the

commenter.

In the second case, the commenter argued that coatings wi th a viscosity of 200 centipoise or greater should be exempt from the spray application equip ment requirements. The commenter noted that South Coast AQMD Rule 1168, Adhesive and Seala nt Applications, contains the same exemption. 67 According to the commenter, these high-viscosity coati ngs have poor flow characteristics and low VOC and organic HAP content. Th e commenter argued that VOC solvents would have to be added to these compounds to lower the viscosity and allow for spraying with an HVLP or equivalent spray gun, and the additi on of VOC solvents to these coatings would likely result in greater emissions than if a conventional spray gun were used.

Response: The EPA agrees with the commenter on the need for an exemption from the application equipment rules for coatings that contain l ess than 20 grams of VOC per liter of coating. The EPA's complete response to this part of the comment can be found in section IV.C.3 in the preamble to the final rule amendments.

66 South Coast AQMD Rule 1124(l)(13); Antelope Valley AQMD Rul e 1124(l)(13).

67 South Coast AQMD Rule 1168(c)(5)(H).55

The EPA disagrees with the commenter on the need for the exemption from application equipment requirements for coatings with a viscosity of 200 centipoise or greater and this exemption is not being included in the final rule. The So uth Coast AQMD Rule 1168 cited by the commenter applies specifically to adhesive and sealant app lication operations, and it also specifically exempts coating of aerospace components that are subject to South Coast AQMD Rule 1124 (see South Coast AQMD Rule 1168(j)(2)). South Coas t AQMD Rule 1124 does not contain an exemption from the application equipment re quirements for coatings with a viscosity of 200 centipoise or greater. In addition, the EPA is inc luding in the final rule, at the request of the same commenter, an exemption from the application equipment requirements for adhesives, sealants, maskants, caulking materials, and inks, consis tent with other more recent surface coating NESHAP. Therefore, the commenter has not identi fied a technical basis for the additional exemption for high viscosity coatings that wo uld be needed in addition to the exemption from the application equipment requirements f or adhesives and sealants (among other materials) added to the final rule.

Comment: One commenter (0830-0028) argued that 40 CFR 63.745(f)(3) should be revised to allow the use of detailing guns or airbrushes for all spec ialty coating application operations, and not just the two exemptions currently in the rule at 40 CF R 63.745(f)(3)(i) and (iv). The commenter argued that several California rules allow th e use of small detailing guns and airbrushes for all specialty coating operations, 68 and because these rules are the basis for the EPA’s MACT determination, the final EPA rule should be con sistent with these rules.

Response: The EPA agrees that the use of airbrushes and detailing guns should be allowed for all specialty coating operations. The EPA's complete res ponse to this comment can be found in section IV.E.3 in the preamble to the final rule amendm ents.

Comment: One commenter (0830-0028) argued that 40 CFR 63.745(f)(1) should be revised to allow the use of high-efficiency air-assisted airless s pray guns, airless spray guns, screen printing, and inkjet printing for application of specialty c oatings because these technologies are equivalent to or better than HVLP. The commenter argued that under CAA Section 112(h)(3), the Agency must allow alternative equipment that achie ves equivalent emission reductions to the equipment prescribed as MACT. The commenter also noted that under other NESHAP (e.g., 40 CFR 63, subparts JJ and HHHHHH), the EPA has determined th at air-assisted airless and airless spray guns are equivalent to HVLP and electrostatic spray, which EPA has designated as the MACT for aerospace specialty coatings. The commenter a lso noted that subpart HHHHHH allows the use of air-assisted airless spray guns and airl ess spray guns (in addition to HVLP) for aerospace surface coating operations at area sources. Fi nally, the commenter noted that several state and regional air agencies allow the use of air-a ssisted airless spray guns and airless spray guns as equivalent to HVLP and included copies of two permit s from the Antelope Valley AQMD and the Georgia Environmental Protection Division.

68 Antelope Valley AQMD Rule 1124(G)(12); Mojave AQMD Rule 1118(c) (1); Bay Area AQMD Rule 8-29- 310.3; South Coast AQMD Rule 1124(l)(14).56

Finally, the commenter argued that screen printing and in k jet technology should be listed as approved application methods because they each achieve nea rly 100 percent transfer efficiency, which is higher than the transfer efficiency of HVLP spr ay guns.

Response: The EPA agrees with the commenter. The EPA's complet e response to this comment can be found in section IV.E.3 in the preamble to the fi nal rule amendments.

Comment: One commenter (0830-0028) argued that the EPA should provide an alternative to using the equivalency demonstration requirements in 40 CFR 63.750(i). The commenter argued that the method in 40 CFR 63.750(i) is overly burdensome, espec ially for specialty coatings, because it requires testing on parts of a similar configur ation to the actual parts being coated, and because of the number of specialty coatings used at most facilities. The commenter recommended that for specialty coatings, the EPA shoul d allow a facility to use any application

method that achieves emission reductions or a transfer e fficiency equal to or better than the methods approved in the rule (HVLP, electrostatic spray, air-assisted airless, and airless), and

that EPA should allow facilities to use a method of it s choice to demonstrate equivalency. The commenter argued that clarifying that facilities may demo nstrate either equivalent emission reductions or transfer efficiency would increase flexibil ity in the rule by allowing the use of either type of equivalency method. The commenter recomm ended that the following language be added to 40 CFR 63.745(f):

For specialty coatings, any other coating application m ethod capable of achieving emission reductions or a transfer efficiency equivalent to or better than that provided by HVLP, electrostatic spray, air-assisted airless, or a irless application. Any owner or operator using an application method pursuant to this subpara graph shall maintain records demonstrating the transfer efficiency achieved

.

Response: The EPA agrees with the commenter. The EPA's complet e response to this comment can be found in section IV.E.3 in the preamble to the fi nal rule amendments.

7.4 Specialty Coating Inorganic HAP Control Requirements

Comment: One commenter (0830-0028) argued that the EPA should clarify t he operations subject to the inorganic HAP requirements by defining “spray-app lied coating operation.” The commenter noted that the term “spray gun” is defined in t he current rule as “a device that atomizes a coating or other material and projects the particulates or other material onto a substrate.” The commenter noted that 40 CFR 63, subpart HHHH HH, which applies to area source aerospace facilities, excludes some specialty coa ting materials (including adhesives, sealants, maskants, and caulking materials) from the def inition of spray applied coating operation because they are not spray applied or are not atomized ev en when they are applied with a spray gun, and instead are emitted in larger particles that settl e near the source and are not emitted. The commenter also noted that certain application methods w ere excluded from the definition of “spray-applied coating operation” in subpart HHHHHH, incl uding the following: powder coating, hand-held, non-refillable aerosol containers, or non-atomizing application technology, including, for example, paint brushes, rollers, hand wipi ng, flow coating, dip coating, electrodeposition coating, web coating, coil coating, to uch-up markers, and marking pens.57

The commenter recommended that the operations subject to t he inorganic HAP control requirements be clarified by adding the following definition to 40 CFR 63.742:

Spray-Applied Coating Operations means operations that apply coatings using a device that creates an atomized mist of coating and deposits th e coating on a substrate. For the purposes of this subpart, spray-applied operations do not include the following materials

or activities:

(1) Application of coating using powder coating, hand-held no n-refillable aerosol containers, or non-atomizing application technology, inc luding, but not limited to paint brushes, rollers, flow coating, dip coating, electrodepo sition coating, web coating, coil coating, touch-up markers, marking pens, trowels, spatulas, da ubers, rags, sponges, mechanically and/or pneumatic-driven syringes, and inkjet ma chines.

(2) Application of adhesives, sealants, maskants, caulk ing materials, and inks.

Response: The EPA agrees with the commenter that certain opera tions, which are often performed with specialty coatings, should be specificall y excluded from the inorganic HAP control requirements for spray applied coating operations because they are not, in fact, applied with atomizing spray application equipment. Therefore, t he EPA is adopting the definition that was suggested by the commenter. The suggested definition is c onsistent with the provisions in 40 CFR 63, subpart HHHHH for defining coating operations subjec t to the inorganic HAP control requirements in subpart HHHHHH.

Comment: One commenter (0830-0028) argued that the rule should include a dditional exemptions from the inorganic HAP requirements for speci alty coatings in 40 CFR 63.745(g)(4), and that these exemptions should not require approval from a permitting authority, and the location of these operations should not be specified in the facility’s Title V operating permit because they may be transitory in nature. The addition al exemptions are the following:

• Spray-application of specialty coatings where it is impr actical to perform the operation inside a spray booth. The current rule provides an exemption for operations where it is impractical to perform the coating in a spra y-booth, but requires identification of these areas in the Title V permit. To accommodate the nature and variety of specialty coating operations and to provide flexib ility, EPA should allow facilities to use this exemption without designating an a rea in the Title V permit.

• Spray-application of specialty coatings controlled by equ ipment and/or work practices and vented indoors. Some facilities apply specia lty coatings outside of spray booths, but use work practices and other equipment (including filters) to control the inorganic HAP emissions to the atmosphere to levels tha t are equivalent to what would be achieved in a spray booth with filtration exhauste d to the atmosphere.

• Spray application of three gallons per day or less at a s ingle location at a facility. California air district rules, including South Coast AQM D Rule 481(e)(1) and Antelope Valley AQMD Rule 481(b)(1) provide this low use exem ption that is necessary to accommodate very small operations that res ult in little or no HAP58 emissions. 69 Facilities in these regions use this exemption to apply small volumes of specialty coatings when it is impractical to move the aircraft or part to a coating booth. Often, these coatings are applied during the final assembly of an aircraft or rework of a fully assembled aircraft that are too lar ge to fit in an available coating booth or otherwise cannot be easily moved. Inorganic HAP emissions from these operations are very low due to the small volume of coat ings applied and work practices used to reduce or control overspray.

• Coatings applied from a hand-held device with a paint cup c apacity that is equal to or less than 3.0 fluid ounces (89 cubic centimeters). This exem ption is provided in Subpart HHHHHH to accommodate low volume applications, including operations that use airbrushes, which may occasionally occur in vari ous locations throughout the assembly facility where it is impractical to relocate the aircraft or part to a coating booth. Because the paint cup capacity is limited to 3.0 fluid ounces, operations of this type are inherently limited and, result in little or no inorganic HAP emissions. Providing this exemption for specialty coatings would allow operational flexibility without creating extra HAP emissions.

Response: In addition to our prior responses on our inability to p rovide exemptions given that Congress has not defined volumetrically which sources’ emissions are s mall enough not to warrant mandatory MACT standards, t he EPA disagrees with the commenter on the need for th ree out of the four suggested exemptions, as explained in the followin g paragraphs.

Spray-application of specialty coatings where it is impractical to perfor m the operation inside a spray booth: The EPA is not including this exemption in the final rule because it is important that permitting authorities review and approve the determina tions that it is impractical to perform a coating operation inside a spray booth. The rule current ly provides flexibility through other mechanisms provided in 40 CFR 63.741(f) and in other provisions incl uded in the final rule such that the need for the additional flexibility for special ty coatings requested by the commenter has not been demonstrated by the commenter.

Spray-application of specialty coatings controlled by equipment and/or work practi ces and

vented indoors: The EPA is not incorporating this change into the rule for specialty coatings because it is not permitted for the currently regulated c oating operations. The current specifications in 40 CFR 63.745(g) ensure that all spray applied coating operations achieve MACT for the control of inorganic HAP emissions. If th e rule included an exclusion for spray applied coatings that are vented indoors, then the contr ol of inorganic HAP emissions would be dependent on the configuration of the building and the ven tilation system of that building, and the EPA would have no assurance that inorganic HAP emiss ions would be controlled to a level equal to MACT.

Spray application of three gallons per day or less at a single location at a facility: The EPA is not incorporating this change into the final rule for spe cialty coatings because it is not permitted for the currently regulated coating operations. In the tw o California AQMD rules cited by the commenter, these applicability exemptions apply to the tot al amount of coating applied per day at a location (i.e., facility), and not to any single c oating operation or use of a specialty coating,

69 South Coast AQMD Rule 481(e)(1); Antelope Valle AQMD Rule 481(b)(1).59

as the commenter suggested. The EPA believes that it is unlikely that any facility that is a major source and subject to subpart GG would have such low daily coat ing consumption.

Coatings applied from a hand-held device with a paint cup capacity that is equal to or less than 3.0 fluid ounces (89 cubic centimeters) : The EPA agrees with the commenter. The EPA's complete response to this comment can be found in sect ion IV.E.3 of the preamble to the final

rule.

Comment: One commenter (0830-0030) supported EPA setting inorganic HAP st andards but opposed the proposed standards which is just to apply the sa me standards applicable to other spray-applied coatings to specialty coatings – i.e., filtr ation efficiency requirements based on the use of a spray booth with a particulate filter.

The commenter argued that the EPA has not met the Act’ s stringency requirements for inorganic HAP standards for specialty coating operations because EPA has not considered or proposed standards that would require the “maximum achievable” degree o f inorganic HAP reductions, as CAA § 7412(d)(2) requires. The commenter added that EPA has not considered or assured that it is setting a floor that requires at least the average e mission limitation “achieved” by the bestperforming 12 percent, for existing sources, and the best-perf orming single source, for new sources, as CAA § 7412(d)(3) requires. The commenter noted tha t EPA must perform the requisite floor and beyond-the-floor analysis, based on the emission reductions actually achieved for the inorganic HAPs, including all HAP metals which inc lude cadmium and lead, among others. The commenter explained that this would assure th at, at least, EPA is requiring a 99 percent control efficiency, rather than a range of 10-90 pe rcent efficiency as the proposed rule appears to allow. The commenter disagreed with EPA’s s tatement that it is doing this because this is the “predominant method used” by those other sources. According to the commenter, EPA has admitted “the predominant method used to control in organic HAP emissions from all spray-applied coating operations (including specialty coati ngs) is the use of a spray booth with a particulate filter which generally achieves a high (i.e. , greater than 99 percent) control efficiency” which would suggests that at least the top 12 percent best performing sources are achieving a 99 percent control efficiency – and this is likely to be the average emission limitation these sources have achieved. The commenter argued that EP A may not, therefore, set standards that are any less stringent than 99 percent control effi ciency for existing sources or for new sources, as it proposes to do in violation of CAA § 7412(d)(3) and must assure the “maximum degree” of emission reduction that is “achievable.”

The commenter further noted that EPA has not shown tha t just applying the efficiency control standards for inorganic HAPs will assure the requisite lev el of control of all HAPs, particularly

all metal HAPs. The commenter added that EPA must direct ly regulate or show that an “inorganic HAP”-focused surrogate standard is sufficient to control these pollutants. The

commenter noted that EPA has not shown that it has met the surrogacy test or shown that this proposed standard would adequately control all emitted HAP me tals, as required.

Response: The EPA acknowledges the commenters support for establis hing inorganic HAP emission standard for specialty coating operations. Howe ver, we disagree with the commenter’s assessment of the MACT analysis and stringency require ments for inorganic HAP emissions from specialty coating operations. The information that t he EPA had available for the proposed60

inorganic HAP requirements for specialty coatings is bas ed on compliance with the current standards in 40 CFR 63.745(g). In the analysis of the ICR data and in the search of different information sources described in the MACT memo for spec ialty coatings, the EPA found no information indicating that any facilities were compl ying with more stringent emission limitations than those in 40 CFR 63.745(g). As earlier explained, CAA section 112(d)(3) requires the EPA to promulgate standards that must be at least as stringent a s the average emissions limitation achieved by the best performing 12 percent of existing sources “for which t he Administrator has emissions information.” Our approach to use of available data is suppo rted by NRDC v. EPA , 529 F.3d 1077, 1086) (D.C. Cir. 2008). (The EPA typically has wide latitude in determining t he extent of data-gathering necessary to solve a problem.).

The EPA acknowledges that we erred by referring to 99-percen t control efficiency in the proposal preamble (80 FR 8421) because this was a reference to overall overspray arrestor efficiency, which is readily achievable by good quality spra y booth filters. However, this overall overspray arrestor efficiency should not be compared to the arrestor efficiency requirements for the different aerodynamic particle size ranges in Tables 2 through 5 in 40 CFR 63.745 in the proposed amendments. The same filters that can comply with the requirements in Tables 2 through 5 should also be able to achieve 99 percent efficiency of total paint overspray because most of the paint overspray particles are much larger th an the largest particle size ranges in Tables 2 through 5. To avoid confusion, the EPA should have re ferred to the arrestor requirements in Tables 2 through 5 in the proposed amendmen ts when discussing the types of controls currently in use that were the basis of MACT for specialty coatings.

We also disagree with the comment that we have not sho wn that the standard for inorganic HAP will control all HAP, including metal HAP, and that we have not shown that we have met the surrogacy test. As previously explained, the EPA may use a surrogate to regulate HAP if there is a reasonable basis to do so. We have used PM as a surrogat e to regulate non-mercury metal HAP because “(1) HAP metals are invariably present . . . in PM;” (2) “PM control technology indiscriminately captures HAP metals along with other par ticulates;” and (3) “PM control is the only means by which facilities achieve reduction in HAP m etal emissions.” National Lime v.

EPA , 233 F.3d at 639. Here, the filtration controls in the cur rent rule and which we proposed to extend to specialty coating operations are equally effecti ve for all inorganic HAP that are emitted from spray applied coating operations. All of the inorgani c HAP emitted, including metal HAP, are “invariably present” in PM, and the arrestor efficien cy standards will, therefore, “indiscriminately capture” all of the inorganic HAP that are emitted.

Comment: One commenter (0830-0028) stated that EPA should allow inte rlock systems as an alternative to daily pressure drop and water flow reading s on coating booths, as this type of system automatically shuts off the air supply to the spra y guns if the monitored parameters are out of range. The commenter referenced EPA’s proposed interlock option for the Secondary Aluminum NESHAP [79 Fed. Reg. 72874, 72904 (December 8, 2014)], noting that EPA should provide a similar option in this rule. The commenter al so noted that manual recordkeeping or automatic data-logging to meet the requirements are time-c onsuming and expensive, so the interlock system option would reduce the monitoring and re cordkeeping burden for regulated facilities while ensuring that coating operations cease w hen the parameters are out of range.61

Response: The EPA agrees that these types of interlock systems can reduce the monitoring and recordkeeping burden associated with the use of spray booths to control inorganic HAP emissions from spray-applied coating operations and has inc luded this option in the final rule.

7.5 Specialty Coating Compliance Deadline

Comment: Several commenters (0830-0026, 0830-0027, and 0830-0028) argued that the EPA should provide a three-year compliance period for special ty coatings rather than the proposed one-year period. All commenters argued that additional tim e is needed to ensure the replacement specialty coatings meet the needed performance requireme nts specified by aircraft manufacturers, DoD, FAA, NASA, or other countries' gove rnment agencies.

One commenter (0830-0027) argued that additional time is needed fo r coating manufacturers to develop reformulated coatings to meet the proposed limits based on the CTG, to test the coatings to meet customer performance specifications, and to implem ent changes to raw material supply chains, product lines, and distribution channels to ensure com pliance by the deadline and to mitigate the effect of obsolete products and product informa tion.

One commenter (0830-0026) argued that more time is needed to det ermine whether each coating is compliant, engineer new coating formulations, test the new formulation to ensure it meets the requirements of the aircraft manufacturers, and incorpor ate the new formulation into the material specifications and add the coating to the qualified product list for the aircraft. The commenter noted that the EPA acknowledged the lengthy period of time needed to qualify new coatings with respect to the technology review performed for primer and topcoat operations.

One commenter (0830-0028) argued that one year is shorter tha n has been provided in any other surface coating NESHAP. The commenter noted that the CT G limits generally have been applied only to facilities in non-attainment areas, and facili ties in attainment areas may be faced with the need to reformulate some coatings. The commenter also argued that the application equipment and spray booth filtration requirements for specialty co atings will also be new requirements for all facilities using specialty coatings, and additional time may be needed to revise Title V operating permits for new or upgraded spray booths, or to allo w for averaging or alternative compliance demonstrations. The commenter added that, b ecause of the large number of specialty coatings, additional time is also needed to develop compl iance systems (even for facilities that previously were required to comply with the primer and topc oat operation standards), determine the VOC and HAP content of these coatings, and setting up recordkeeping and reporting

systems.

One commenter (0830-0027) argued that the original surface coa ting NESHAP and the recent RTR rules for surface coating have all included three-year compliance dates for the standards or for any significant changes to the existing standards. T he commenter argued that this time is needed by both the coating manufacturers to reformulate coatings and for the regulated operations to procure compliant products and implement new control techniques.

Response: We agree with the commenters on the need for the thr ee-year compliance period. The EPA's complete response to this comment can be found in section IV.J.3 in the preamble to the

final rule amendments.62

Comment: One commenter (0830-0027) asked EPA to include in the final ru le a sell-through provision that will allow aerospace facilities to use exi sting products for a period of up to 2 years beyond the compliance date. The commenter argued that in addition to the time needed for product reformulation and requalification, coating manufac turers will still need to supply the industry with current products that meet customer specificat ions prior to the compliance date of

the final rule.

Response: The EPA is not including the 2-year sell through provision suggested by the commenter in the final rule. As previously explained, u nder CAA section 112(i)(3), the EPA must require sources to comply as expeditiously as practicable, but no lat er than 3 years after promulgation of the standard. The EPA’s construct has recently been upheld in Assn. of Battery Recyclers v. EPA

, 716 F.3d 667 (D.C. Cir. 2013). “Although section 112(i)(3)’s three-year maximum compli ance period applies generally to ‘any emissions standard . . . promulgated un der [section 112],’. . . section 112(f)(4)’s two-year maximum applies more specifically to standards ‘under this section,’ i.e., section 112(f).” Id . at 672 (Alteration in original). Allowing a 2-year sell through provision would mean that some facilities may not be achieving MACT for a period of up to 2 years after the compliance date for existing sources. Aerospace faciliti es will need to begin transitioning to compliant coatings in advance of the 3-year complianc e deadline so that they have depleted their inventories of non-compliant coatings by that deadline.

7.6 Complying with the Proposed Specialty Coating Limits

Comment: One commenter (0830-0028) requested that the EPA include a mec hanism to obtain approval to use essential coatings for which reformulati on cannot be achieved. The commenter argued that it is not possible to determine whether each a nd every specialty coating can comply with the proposed limits because of the large number of specialty coatings, the lack of formulation data available to aerospace facilities, t he need to assign each coating into one or more of the specialty coating classifications, and the length of the comment period. The commenter argued that the need for the suggested mechanism w ould not be eliminated by the averaging provisions because the averaging provisions do not allo w averaging between specialty coatings and primers or topcoats, and it would not benefit facilities that use only a few coatings.

The commenter also noted that once an aircraft is cer tified, it is difficult to change the coatings used without having to repeat at least part of the certific ation process.

Response: The EPA is not including this mechanism in the final rule. It is not included in the CTG, nor is it included in the various state rules that have adopted the CTG and which are the basis for MACT for specialty coatings.

Comment: One commenter (0830-0028) stated that industry members will c ontinue to review specialty coatings to determine if they can meet the pr oposed limits and the commenter will submit that information to the EPA, even if it is outs ide the public comment period, so that the EPA can address those coatings in the final rule or ind icate how they can be addressed in a caseby-case mechanism to address coatings that cannot meet t he standards.

Response: As earlier explained, CAA section 112(d)(3) requires the EPA to promulgate sta ndards that are based on emission limitations achieved by the best performing so urces “for which the Administrator has emissions information.” Our approach to use of av ailable data is also supported by63

NRDC v. EPA , 529 F.3d 1077, 1086) (D.C. Cir. 2008). (The EPA typically has wide latitude in determining the extent of data-gathering necessary to solve a proble m.).

Consistent with CAA section 307(d)(3), the EPA has provided the “comment period” for the proposed rule. (80 FR 8392). Any information or data that are submitted after the end of the public comment period cannot be considered in the final rulem aking for this action. Additionally, we note that the EPA is bound by a consent decree to si gn a final rule by November 19, 2015, and any additional notice and public comment period based on new data would make it impossible to comply with that deadline. Parties can alw ays petition for reconsideration under CAA section 307(d)(7)(B).

Comment: One commenter (0830-0028) recommended that the organic HAP and VOC standards should not apply to the recoating of assembled ai rcraft if original formulations are used. The commenter argued that as long as an aircraft is in service, it must be maintained in accordance with the instructions of the original equipmen t manufacturer (OEM) with materials that conform to its certified configuration to maintain airworthiness. The commenter argued that aerospace facilities occasionally work on an older air craft that was assembled with specialty coatings that would not meet the proposed organic HAP or VOC standards and for which there will not be a replacement coating that meets the speci fications for the aerospace vehicle or component, including compatibility with the substrate and existing coatings, and it will likely be economically impractical to reformulate a coating tha t may be sparingly used on reworked aircraft. The commenter noted that South Coast AQMD Rule 1124 exempts such operations from

its limits. The commenter recommended that EPA should provide this limited allowance to the organic HAP and VOC standards for specialty coatings by addin g the following provision to 40

CFR 63.741:

The provisions of Section 63.745(c)(5) and (6) shall not apply t o the recoating of assembled aircraft at rework facilities if original c oating formulations are used.

Response: The EPA disagrees with the commenter on the need for this provision. Subpart GG currently does not regulate the rework of aircraft or air craft components if the holder of the Federal Aviation Administration (FAA) design approval, or the holder's licensee, is not actively manufacturing the aircraft or aircraft components. (See 40 CFR 63.741(f).) The EPA believes that this provision in the current addresses the issues a ssociated with older aircraft raised by the

commenter.

Comment: One commenter (0830-0028) recommended that compliance avera ging should be permitted between and among specialty coating classificat ions. The commenter noted that the EPA proposed that instead of complying with the individual o rganic HAP and VOC specialty coating limits at 40 CFR 63.745(c), facilities may use the monthly volume-weighted average of specialty coatings to demonstrate compliance with thes e limits, but averaging would be prohibited between different classifications of specialty coatings. The commenter argued that averaging should be allowed between all classifications of specialty coatings, as the current rule allows averaging between types of primers (e.g., averagi ng is allowed between primers applied to large commercial aircraft and general primers). The c ommenter noted that Under the Miscellaneous Metal Parts and Products NESHAP (40 CFR 63, s ubpart MMMM), facilities are64

allowed to demonstrate compliance with the coating limits by developing a facility-wide emission rate calculated as the weighted average of the four different limits.

Response: The EPA did not propose to allow emissions averaging amo ng specialty coatings in different categories and subject to different emission limits, and did not discuss such an approach in the proposal preamble or other supporting documents, and the refore, this comment is beyond the scope of this rulemaking.

The averaging language in 40 CFR 63.743(d) specifically prohibits av eraging between Type I and Type II chemical milling maskants. In addition, the r ule does not include any method or equation for calculating the limit with which a facilit y would need to comply if it were averaging among coating types that were subject to different limits

.

The averaging language in 40 CFR 63.743(d) was added in the amendme nts that were finalized on March 27, 1998 (63 FR 15006), and the EPA did not, through this rul emaking, reopen the opportunity for comments on previous actions taken. As al so earlier noted, EPA considers these comments as beyond the scope of today’s action. The la nguage of that section reflects the primer and top coat categories that were in the rule at tha t time in 40 CFR 63.745: primers, topcoats, and self-priming topcoats. The preamble to the final rule included the following discussion of the feasibility of averaging across coating categories (63 FR 15012):

“A workable scheme for averaging across coating types was not developed because the format of the coating limits in the rule as originall y promulgated creates inherent difficulties in making equitable comparisons/calculatio ns of actual emissions from coating categories with different limits . In order to include effective emissions averaging provisions for different coating categories (e.g., primer s, topcoats, and maskants) or other emission sources, the format of the entire rule would have to be overhauled. Such changes are now beyond the scope of the work involved in finalizing these amendments to the aerospace rule.” [Emphasis added.]

Comment: One commenter (0830-0028) recommended that the rule should all ow addition of HAP-free solvents to specialty coatings that meet the organic HAP and VOC limits as supplied by the coating manufacturer. The commenter argued that in dustry members have identified several specialty coatings that meet the organic HAP a nd VOC content limits as supplied by the manufacturer but that would no longer meet the VOC limit “as applied” when solvents are added as recommended in the manufacturing specification. In th ose cases, the solvents added contain VOC, but no HAP, such as primers that are applied in warm weather. The commenter suggested that facilities would be required to keep records demonstrat ing compliance with the limits as supplied and that the solvents added do not contain HAP. The c ommenter argued that such a change would be equivalent to the proposed standards becaus e (1) the coatings meet the organic HAP and VOC content limits as supplied, thereby effectiv ely limiting the HAP content of the coating, and (2) the solvents added do not contain HAP, suc h that the coatings would remain complaint with the organic HAP limit “as applied.”

Response: The EPA agrees with the commenter. The EPA's complete response to this comment can be found in section IV.E.3 in the preamble to the fi nal rule amendments.65

Comment: One commenter (0830-0028) recommended that where the EPA has found in approving a RACT limit for a State or region that it is e quivalent to the CTG, the EPA should allow in the final rule that compliance with the RACT limit is equivalent to the MACT for complying with the specialty coatings limits. The commen ter also recommended that the EPA should encourage states and local governments to submit the ir RACT or other regulations to EPA for equivalency determinations pursuant to Section 112(l) o f the Act and Subpart E of Part 63. The commenter noted that, under 40 CFR 63.93, a State may seek approval of State requirements that differ from a Section 112 NESHAP for w hich they would substitute. The commenter argued that the EPA should provide for streamline d approval in the final rule for state rules that have been approved as RACT, and that such an approach would be consistent with the intent of Section 112(l) of the CAA and would al so fulfill Congress’ direction to harmonize aerospace industry CTG-based standards with the NESHAP requirements. 70

Response: The EPA disagrees with the commenter that state appro ved RACT limits equivalent to the CTG should be allowed as equivalent to MACT for c omplying with the specialty coating limits. As previously explained, Section 112(d)(3) of the CAA requires the EPA to promulgate standards for major sources of HAP that are based on control technology perfo rmance. For existing sources, MACT standards must be at least as stringent as the averag e emission limitation achieved by the best performing 12 percent of existing sources (for which the Administ rator has emissions information) or the best performing 5 sources for source categories with less than 30 sources. For new sources, the MACT standards must be at least as stringent as the con trol level achieved in practice by the best controlled similar source. CAA Section 112(d)(3). Thus, the EPA is required to establish uniform limits equal to MACT under section 112 of the CAA. The CTG is a guideline document, and state may deviate from it in developing RAC T standards for controlling VOC emissions. Therefore, the EPA cannot determine if all approved RACT standards are equal to MACT. If the approved RACT standards are equal to the CTG limits that are being promulgated as MACT in the final rule, then there is no clear be nefit to facilities or states to justify the additional administrative burden on facilities, states , or the EPA in the equivalency determinations recommended by the commenter.

Comment: One commenter (0830-0028) argued that the EPA should expand the low-volume exemption in 40 CFR 63.741(g) to allow a total of 200 gallons of spe cialty coatings in addition to the 200 gallons of primers, topcoats, and chemical milling maskants. The commenter noted that in the rule the exemption would not be expanded fro m the current total of 200 gallons. The commenter argued that the low volume exemption is criti cal for the aerospace industry because for many applications subject to detailed specifications, only one formulation is available, and the small volume of coating used does not justify the c ost to reformulate.

The commenter argued that because of the total number of specialty coatings, an additional 200 gallons is needed separate from the exemption for primers , topcoats, and chemical milling maskants. The commenter argued that the original 200 gallon exemption was considered part of MACT for primers, topcoats, and chemical milling maskan ts, and forcing facilities to allocate part of that exemption to specialty coatings would make t he MACT for primers, topcoats, and

70 42 U.S.C. § 7511b(b)(3); H.R. Rep. No. 101-490 At 249 (1990) (Rep. Acc ompanying H.R. 3030) Reprinted In 2 Senate Comm. On Env’t and Pub. Works, 103d Cong., A Legislati ve History of the Clean Air Act Amendments of 1990, At 3273 (1993).66

chemical milling maskants more stringent. The commente r argued that a change to the MACT standard can be made only if there is a finding of a techn ological advancement under CAA section 112(d)(6) or of unacceptable risk under CAA section 112(f ). The commenter noted that the EPA has made neither of those findings.

The commenter also noted that the CTG that is the bas is for the specialty coating limits includes a 200-gallon low-volume exemption for specialty coatings, separate from the 200-gallon exemption for primers, topcoats, and chemical milling mas kants.

The commenter recommended the following changes to the proposed language in 40 CFR 63.741(g):

The requirements for primers, topcoats, specialty coati ngs and chemical milling maskants in §§ 63.745 and 63.747 do not apply to the use of low-volume coating s in these categories for which the annual total of each separate formulation used at a facility does not exceed 189 liters (50 gal), and the combined annual total of all such primers, topcoats, specialty coatings and chemical milling maskants used at a facility does not exceed 757 liters (200 gal). The requirements for specialty c oatings in § 63.745 do not apply to the use of low-volume coatings in this category for which the annual total of each separate formulation used at a facility does not exc eed 189 liters (50 gal), and the combined annual total of all such specialty coatings used at a facility does not exceed 757 liters (200 gal). Primers, topcoats and specialty coatings exempted under paragraph (f) of this section and under § 63.745(f)(3) and (g)(4) are not included i n the 50 and 200 gal limits. Chemical milling maskants exempted under § 63.747(c)(3 ) are also not included in

these limits.

Response: The EPA is not expanding the low-volume exemption in 40 CFR 63.741(f) to include a 200 gallon exemption for specialty coatings, in addition to the existing 200 gallon exemption for primers, topcoats, and chemical milling maskants. The exemption recommended by the commenter is not included in the Aerospace CTG, nor is it included in any of the state and regional rules based on the CTG. The commenter did no t provide any data or information on specific examples of specialty coatings used in applicati ons subject to detailed specifications where only one formulation is available.

We also disagree with the commenter that the basis f or MACT for primers, topcoats, and chemical milling maskants included a 200 gallon per year lo w volume exemption for just those coatings, and that the addition of specialty coatings w ould make the MACT for primers, topcoats, and chemical milling maskants more stringent. A s described in section 3.4 of the 1995 background information document for the proposed NESHAP, 71 the California rules on which the EPA based the MACT determination included exemptions o f no more than 250 gallons of coating per year, and no more than 20 gallons per year of i ndividual coatings, for all surface coating operations, including primers, topcoats, and chemic al milling maskants, and specialty coatings. These California rule do not presently include separate low volume exemptions for

71 National Emission Standard for Hazardous Air Pollutant s (NESHAP) for the Aerospace Industry - Background Information for Proposed Standards. Draft. May 1994. EPA Pub lication No. EPA-453-R94-036a.67

specialty coatings. The Aerospace CTG also does not in clude a separate low-volume exemption for specialty coatings.

Comment: One commenter (0830-0028) argued that the rule should be revis ed to clarify that it does not apply to specialty coatings that do not contain HA P. The commenter noted that proposed 40 CFR 63.741(f) includes the following sentence (emp hasis added):

The requirements of this subpart also do not apply to prime rs, topcoats, specialty coatings, chemical milling maskants, strippers, and cle aning solvents containing HAP and VOC at concentrations less than 0.1 percent by mass for carcinogens or 1. 0 percent by mass for non-carcinogens , as determined from manufacturer’s representations, such as in a material safety data sheet or product data sheet, o r testing.

The commenter argued that this could be interpreted to mea n that the rule would regulate coatings that contain no HAP, if they contained VOC a bove the levels specified in that sentence. The commenter argued that this is likely to have been uni ntentional because the EPA has the authority to regulate only sources of HAP under section 112, a nd EPA cannot regulate sources of VOC that are not sources of HAP. The commenter argued ho wever, that aerospace facilities should have the option to use coating with no HAP to de monstrate compliance using the coating content averaging provisions of 40 CFR 63.750(d) and (f) to enco urage the development and use of non-HAP coatings. The commenter recommended that the following provision should be added to 40 CFR 63.741(f) to clarify the exemption:

The requirements of this subpart also do not apply to speci alty coatings containing HAP at concentrations less than 0.1 percent by mass for car cinogens or 1.0 percent by mass for carcinogens, as determined from manufacturer’s representat ions, such as in a material safety data sheet or product data sheet, or testing, except that if an owner or operator chooses to include one or more such coatings in averagin g under § 63.743(d), then the recordkeeping requirements of § 63.752(c)(4) shall apply.

Response: The EPA agrees with the commenter. The EPA's complet e response to this comment can be found in section IV.G.3 in the preamble to the fina l rule amendments.

Comment: One commenter (00830-0028) argued that the EPA should revise th e definition of “coating” in 40 CFR 63.742 to be consistent with other surfac e coating NESHAP. The commenter argued that the current definition is vague, and with the proposed regulation of specialty coatings, it could be read to include products tha t are not considered coating products under other EPA surface coating rules. The commenter argue d that the definition should limit coatings to liquid or mastic materials (consistent wit h the American Society of Testing and Materials definition of coating) and exclude materials th at are excluded from the definition of coating in other EPA rules. The commenter recommended t he following definition of coating:

Coating means a liquid, liquefiable, or mastic composition that is applied to the surface of an aerospace vehicle or component and converted by evapor ation, cross-linking, or cooling, to form a decorative, protective, or functional so lid film or the solid film itself. Coating application with handheld, non-refillable aeros ol containers, touch-up markers, marking pens, or the application of paper film or plastic f ilm which may be pre-coated68

with an adhesive by the manufacturer are not coating opera tions for the purposes of this subpart.

Response: The EPA agrees with the commenter. The EPA's complete response to this comment can be found in section IV.G.3 in the preamble to the fina l rule amendments.



### 8.0 Startup, Shutdown, Malfunction Provisions

Comment: One commenter (0830-0030) supported the removal of the exemptions for emissions during startup, shutdown and malfunction periods. The commen ter agreed that emission standards must apply at all times, as the Clean Air Act requires, which EPA has recognized, and

the D.C. Circuit has held. 72 Further, the commenter also supported that EPA appropria tely recognizes that it may not promulgate any affirmative defe nse for civil penalties in the event of a

malfunction 73 because such provisions are also unlawful, as the D.C. C ircuit has held. 74

Response: The EPA acknowledges the commenter’s support.

Comment: One commenter (0830-0028) noted that while EPA’s intent for the proposed recordkeeping and reporting requirements at 40 CFR 63.752(a)(1) to (3) and 63.753(a)(5) is to apply only to malfunctions of equipment, they could be int erpreted more broadly to require reporting of deviations from any applicable requirement. If finalized as proposed, the commenter stated they could result in unnecessary and burdensome requi rements that overlap with detailed recordkeeping and reporting provisions in the current rule and deviation reporting requirements in the facilities’ Title V permits. The commenter fur ther noted that EPA should remove the proposed additions and simply require malfunction reportin g under General Provisions, or if EPA keeps the new provisions it must modify them to clear ly indicate that they apply only to

malfunctions.

Response: The commenter is incorrect. The EPA does not intend tha t the requirements in 40 CFR 63.752(a)(1) to (3) and 63.753(a)(5) should apply only to malfunc tions of equipment. Instead, the EPA intends that recordkeeping and reporting re quirements that would be applicable to normal operations should also apply to startup and shutdown. They are general requirements to report deviations, and more specific requirements, such as creating and retaining records of occurrences and durations of malfunctions, that are include d in the other paragraphs of 40 CFR 63.752. As described in section IV.E.3 of the proposal preamble , the EPA is required by recent court decisions to revise the provisions of the NESHAP rega rding emissions during periods of startup, shutdown, and malfunction, and these changes requ ire provisions that differ from the current General Provisions, and which may differ from a facility’s Title V permit requirements. (80 FR 8425).

Comment: One commenter (0830-0028) stated that the existing reporting r equirements in the Aerospace NESHAP and Title V permit require only the info rmation that is readily attainable and necessary to determine compliance, for example, re porting instances when a coating

72 42 U.S.C. §§ 7602(k), 7412; 80 Fed. Reg. at 8423; Sierra Club , 551 F.3d 1019.

73 80 Fed. Reg. at 8424.

74 42 U.S.C. §§ 7413, 7604; NRDC v. EPA , 749 F.3d 1055, 1057 (D.C. Cir. 2014).69

operation was not immediately shut down when the pressur e drop across the particulate filter was outside of recommended parameters. The commenter noted tha t the proposed requirements will now also require a facility to provide an estimate of t he quantity of each pollutant emitted over the emission limit, but it is not practical for a fac ility to determine or even estimate the volume of excess emissions from a coating booth, so this should not be required.

Response: The EPA disagrees with the commenter and we are retai ning the requirement as proposed to report an estimate of the quantity of each r egulated pollutant emitted over any emission limit and a description of the method used to es timate the emissions over the emission limit. This requirement will ensure that there is adequate information to allow the EPA to determine the severity of the failure to meet an applica ble standard and to provide data that may document how the source met the general duty to minimize e missions during an exceedance event. We disagree with the commenter that it is not p ossible to estimate emissions during these types of events. The rule provides facilities the flexibi lity to select the most appropriate method to estimate emissions based on process knowledge and the ci rcumstances of each situation. Examples of such methods would include mass balance calcul ations, measurements when available or engineering judgment based on known process par ameters (e.g., coating HAP content and application rate or control device efficienc ies).

Comment: One commenter (0830-0028) argued that the proposed recordkeeping and reporting requirements are contrary to the Clean Air Act in tha t they appear to require reporting of violations per inclusion of the wording “failure to meet a n applicable standard.” The commenter stated that CAA Section 504(c) provides that Title V facil ities are required to report deviations from—not failure to meet—permit requirements. The comme nter further noted that EPA should use the statutory language instead of adopting a new term which has not been defined. The commenter explained that a deviation from a particular pe rmit term might be excused such that it is not a violation, and stated that requiring a source to concede a violation is contrary to the statute. If EPA keeps the new provisions, it must revise them to state that facilities are only required to report deviations and not failures to meet the s tandard.

Response: The EPA disagrees with the commenter. As previously ex plained in the preamble to the proposed rule (80 FR 8426, February 17, 2015), the EPA intends that these requirements would apply to the failure to meet any applicable standard in subpart GG. They are general requirements to report deviations, and more specific require ments are included in the other paragraphs of 40 CFR 63.752. The EPA will use the reported inform ation to determine compliance, the severity of the failure to meet an a pplicable standard, and whether the facility met the general duty to minimize emissions during a malfun ction The language in the proposed

rule does not affect the EPA’s discretion to evaluate each case of an exceedance of an emission limit or failure to meet an applicable standard on a case -by-case basis, as described in section IV.E.3 of the proposal preamble.

Comment: One commenter (0830-0028) stated that EPA should not require compliance with emission limits during malfunctions, or if so, should deve lop standards for malfunctions based on appropriate data. The commenter further noted that the court decisions EPA used to justify requiring compliance during malfunctions do not stand for th e proposition that standards based on normal operations should be applied during periods of abnor mal operation.70

A second commenter (0830-0026) argued that the EPA's proposal t o eliminate the exemption for startup, shutdown, and malfunction events is based on an incorrect reading of Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008) (hereinafter “ Sierra Club ”) and that the EPA is in fact required to provide achievable emission standards for malfunct ions under the CAA. The commenter also argued that Sierra Club does not bar EPA from implementing different emissions standards during startup and shutdown periods, and w ork practice standards for

malfunction events.

The second commenter (0830-0026) argued that Sierra Club does not require EPA to eliminate malfunction provisions, and instead only requires that st andards promulgated under Section 112 of the Clean Air Act must apply at all times. The comm enter argued that the Sierra Club Court held that Congress “required that there must be continuous section 112-compliant standards,” and that the “general duty” requirements of 40 CFR 63.6 were not sufficient because they were

not contained in Section 112. 75 The commenter argued that the Court therefore found the SSM exemption to be in violation of the CAA’s requirement “that some section 112 standard apply continuously.” 76

The second commenter (0830-0026) argued that the court specifica lly noted that, although the blanket SSM exemption was illegal, “continuous emission r eduction” could be achieved “without necessarily continuously applying a single standar d.” 77 The commenter argued that the court found that Congress’s primary purpose in requiring “con tinuous” regulations was to ensure that regulation was not “intermittent” and that Congres s did not intend to require that one uniform standard apply at all times. The commenter noted t hat the court pointed to Section 112(h) as an option to allow implementation of work practi ce standards rather than numeric emissions limits as a 112-compliant option for regulat ing SSM events, by noting that EPA had “not purported to act under section 112(h),” though it coul d have. 78

The second commenter (0830-0026) argued that the EPA is still authorized to promulgate emissions standards that would apply during periods of malfu nction, so long as the standards are rooted in Section 112. The commenter pointed to a memorandum issued by the EPA’s Office of

Civil Enforcement 79 that the commenter argued indicated that the vacatur of the SSM exemption would not impact rules that “include specific regulatory te xt that exempts or excuses compliance during SSM events, and such regulatory text is in addition to, or in lieu of, a cross-reference to” the general duty provisions in 40 CFR 63.6, and the Sierra Club decision would only affect specific rules if the rule did not contain independent SS M provisions.

The second commenter (0830-0026) argued that EPA's rationale th at the EPA cannot account for malfunctions in setting emission standards because of the different types of malfunctions that can occur and the difficulty of predicting or accounting for the frequency, degree and duration of various malfunctions that might occur, is not valid bec ause Section 112(h) provides option for accounting for malfunctions. The commenter argued that S ection 112(h) work practice standards

75 Sierra Club , 551 F.3d at 1027-1028.

76 Id. at 1028.

77 Id . at 1027.

78 Id . at 1028.

79 See U.S. EPA Memorandum re Vacatur of Startup, Shutdown, and Malfunction (SSM) Exemption (40 C.F.R. §§ 63.6(f)(1) and 63.6(h)(1)) (“Kushner Memo”) (July 22, 2009).71

are permitted where it is “not feasible...to prescribe or e nforce an emission standard,” including where “the application of measurement methodology to a particular class of sources is not practicable,” and can be used to address the difficulties des cribed in EPA's rationale. The commenter argued that Section 112(d)(1)(E) authorizes EPA to establish emission standards that combine numeric elements with work practice elements s o that some Section 112 standard would apply at all times as required by the Sierra Club decisi on.

A third commenter (0830-0026) argued that the EPA is required to account for malfunctions in setting achievable technology based standards under Sectio n 112(d), and that these standards must be based on actual performance. 80 The commenter argued that the EPA has acknowledged that malfunctions are not reasonably preventable and ca n result in emissions that are above normal levels, but notes that the EPA has argued that not hing in section 112 directs the Agency to consider malfunctions in determining the level “achieve d” by the best performing sources when setting standards. The commenter argued that the EP A is incorrect to assume that it has no obligation to consider malfunctions in setting emission standards, and that instead, the EPA must consider emissions during malfunctions in order to set sta ndards that reflect actual performance. The commenter argued that this conclusion is supported by judicial precedent 81 that requires the EPA to consider malfunctions and implement different e mission standards or work practice standards for startup, shutdown, and malfunction events.

Response: As explained at proposal, in Sierra Club v. EPA , 551 F.3d 1019 (D.C. Cir. 2008), the United States Court of Appeals for the District of Colu mbia Circuit vacated the startup, shutdown, and malfunction (SSM) exemptions contained in s ection 63.6(f)(1) and (h)(1) of the Part 63 General Provisions. (80 FR 8423-24, February 17, 2015). When incorporated into CAA section 112(d) regulations for specific source categories, t hese two provisions exempted sources from the requirement to comply with the otherwise appl icable section 112(d) emission standard during periods of SSM. In Sierra Club , the court explained that under section 302(k) of the CAA, emissions standards or limitations must be continuous in nature. The court then held that the SSM exemption violates the CAA's requirement that some section 112 standard apply continuously.

To ensure that some section 112 standard applies at all tim es, we are specifying that the SSM exemption in the 40 CFR part 63 General Provisions does not apply to subpart GG and clarifying that the emission limits apply at all other times, i ncluding during periods of malfunction.

Regarding periods of malfunction, the Clean Air Act doe s not allow EPA to provide “affirmative defense” provisions into NESHAP. In NRDC v. EPA , 749 F.3d 1055(D.C. Cir. 2014) the D.C. Circuit vacated a regulatory provision establishing an affirm ative defense to civil penalties for

80 See Nat’l Assn. of Clean Water Agencies v. EPA , 734 F.3d 1115, 1158 (D.C. Cir. 2013) (“[I]t is reasonable to expect that the incinerator on which the MACT floors are based should be able to ‘achieve’ the MACT floor ‘in practice,’ which it could not do unless ‘achieved in prac tice’ meant ‘achieved under the worst foreseeable circumstances.’”).

81 For example, the commenter argued that the D.C. Circuit acknowledged that malfunctions were an “inescapable aspect of industrial life” and agreed that EPA must allo w for malfunctions in setting technology-based emission standards. Portland Cement Assn. v. Ruckelshaus, 486 F.2d 375, 398-99 (D.C. Cir. 1973)72

violations of emission standards caused by unavoidable malfu nctions. The court found that the authority under the CAA to determine penalty amounts lies exclusively with the courts.

In light of NRDC , the EPA is no longer including regulatory affirmative defense provisions in its rules. However, if a source is unable to comply with a n emission standard as a result of a malfunction, the EPA may use its case-by-case enforcem ent discretion to provide flexibility in deciding if a penalty is appropriate. Further, in an EPA or citizen enforcement action, the court has the discretion to consider any defense raised and dete rmine whether penalties are appropriate.



### 9.0 Electronic Reporting Provisions

Comment: One commenter (0830-0030) supported the EPA's proposal that r equires performance test and other compliance information to be submitted through electronic reporting using the portal and software developed for this purpose. 82 The commenter added that the EPA must ensure this information is also promptly made availa ble online to the public in an accessible format and supported the WebFIRE data being publicly available. However, the commenter

noted that it is not in a form that most members of t he public can understand or interpret. The commenter recommended that the EPA should strengthen t he electronic portal to synthesize the data and assist the public in analyzing the raw data and repo rts that facilities submit. The commenter argued that updating the electronic reporting syst em to assist the public in reviewing and understanding the reported data would be consistent with t he 1994 Environmental Justice Executive Order (No. 12898) and EPA’s renewed commitment to strengthen the public availability of information for affected communities, a s part of Plan EJ 2014. 83

Response: The EPA acknowledges the commenter’s support for the pro posal to require performance test reports to be submitted through electronic reporting. However, the structure and format of the data provided in WebFIRE is beyond the scope of this rulemaking. The EPA notes that currently the WebFIRE database has over 3500 reports available for public review. Most of these reports are a portable document format (pdf) file, w hich is a format that can be easily reviewed by anyone. Performance test and performance evalu ation reports are available as both an extensible markup language (XML) file and an Electronic Reporting Tool (ERT) file. The ERT is a free download available from the EPA at http:// www3.epa.gov/ttnchie1/ert/. The

current version of the ERT is a Microsoft Access dat abase program, and as such, users must own a copy of Microsoft Access in order for the program to work. For users who do not own a copy of Microsoft Access, a runtime version is available t hrough Microsoft. In order to view ERT files, the user must open the file in the ERT program. If a user does not wish to review the data in the ERT, once the ERT file is opened in Microsoft Access, a pdf file of the entered data can be created. Additionally, a majority of the ERT files hav e a pdf file of the entire stack test report attached. This can be obtained by opening the file in the ER T program and looking at the list of

attachments.

82 80 Fed. Reg. at 8422.

83 Plan EJ 2014, supra note 6.73



### 10.0 Alternative Compliance Demonstration

Comment: Two commenters (0830-0027, 0830-0028) supported the use of VOC content a s a surrogate for HAP content and argued that it is at least as protective as using HAP content and is

less burdensome. The two commenters added that the current NESHAP addresses the issue of solvents that are HAP, but exempt from the definition o f VOC (methylene chloride, perchloroethylene, and 1,1,1-trichloroethane), by allowing sour ces to rely on VOC only as long as the coating does not contain exempt solvents (see 40 CF R 63.750(c)(1)). The commenters recommended that the same approach be used with the VOC li mits for specialty coatings to address any discrepancy between VOC and HAP content while reducing the regulatory burden of

the rule.

Response: The EPA agrees with the commenters that facilities should have the option to use VOC content as a surrogate for HAP content and will inc lude it in the final rule for specialty coatings that do not contain certain halogenated solvents that are excluded from the definition of VOC. As previously explained, EPA may use a surrogate to r egulate HAP if there is a reasonable

basis to do so. National Lime Assn., 633 F.3d at 639. As also previously explained, with the exception of the three halogenated solvents, all HAP a re also VOC and we are setting the same limit for VOC and organic HAP such that the organic HAP co ntent cannot exceed the VOC

limit.

Specialty coatings that contain these halogenated solve nts will have to use HAP content to demonstrate compliance, but they will have the option t o still use manufacturer’s supplied data on the HAP content to demonstrate compliance. Addition ally, in order to verify the HAP content of such coatings, the EPA is also adding EPA Method 311, An alysis of Hazardous Air Pollutant Compounds in Paints and Coatings by Direct Injection Int o a Gas Chromatograph, to 40 CFR

63.750 as the EPA reference method to confirm the HAP cont ent of coatings. In the event of any inconsistency between the EPA Method 311 test data and man ufacturer’s supplied formulation data, that is, if the EPA Method 311 value is higher, the EPA Method 311 test will govern unless after consultation, the facility can demonstrate to t he satisfaction of the enforcement agency that

the formulation data were correct.

Comment: Two commenters (0830-0027, 0830-0028) agreed that manufacturer’s documentation of the HAP or VOC content of the coating s, such as MSDS and product data sheets, should be accepted for demonstrating compliance f or specialty coatings as proposed in 40 CFR 63.750(c), (e), (k), and (m). One commenter (0830-0027) added tha t this approach has been adopted in other national, state, and local VOC regulati ons and noted that coating manufacturers have the best understanding of their products because they h ave to collect information on each of their raw materials and their coating formulations fo r other regulatory purposes, such as the preparation of MSDS to comply with OSHA's Hazard Communic ation Standard. The same commenter argued that this would also be more cost effecti ve than performing EPA Method 24 testing on each coating formulation.

Response: The EPA acknowledges the commenter’s support.

Comment: One commenter (0830-0028) argued that certain clarifications are needed to reduce compliance costs and bring them closer to the EPA's es timated compliance costs. The74

commenter argued that first, the rule should confirm that facilities should be able to rely conclusively on coating manufacturer VOC data to demonstr ate compliance with the VOC content limits. The commenter noted that, because the only reason to provide VOC content data is for regulatory purposes, one can assume that the VOC content listed is the regulatory VOC content (that is, less water and exempt solvents). Th e commenter suggested that this assumption could be made explicit in the rule by adding the following sentence or an equivalent clarification to 40 CFR 63.750(e), (f)(1)(iii), (m), and (n)(1):

Unless stated otherwise on coating manufacturer documenta tion, coating manufacturer supplied VOC content provided in grams/liter (lb/gal) is deem ed consistent with the definition of VOC in 40 CFR 51.100(s) (i.e., less water and exempt solvents).

Second, the commenter (0830-0028) argued that the rule should co nfirm that facilities may use the VOC content data supplied by the coating manufacturer to demonstrate compliance with the organic HAP limits when the coating does not contain exem pt solvents that are also organic

HAP. The commenter noted that this clarification is n eeded to simplify the compliance demonstration because coating manufacturers rarely provide the HAP content on product data or MSDS sheets. The commenter argued that the following se ntence should be added to the end of 40 CFR 63.750(c), (d), (k), and (l):

The coating manufacturer’s supplied VOC content may be us ed as a surrogate for organic HAP content if the coating does not contain exempt sol vents that are HAP.

The commenter (0830-0028) argued that these two changes are nee ded for the EPA to assume in the cost impact analysis for specialty coatings that facilities will not need to perform testing to determine the VOC or HAP content of coatings.

The commenter (0830-0028) argued also that the rule must clar ify that facilities will not be subject to enforcement action if laboratory testing reve als a value over the limit when the manufacturer data shows values that are compliant and n o additional solvents were added by the facility. The commenter argued that EPA needs to provide a safe harbor for companies that reasonably rely on the data supplied by the manufacturer in order to support the EPA’s recordkeeping and reporting burden estimate, consistent with the Paperwork Reduction Act (44 U.S.C. § 3506(c)(1)).

Response: As previously explained, the EPA agrees with the comment er that with the exception of certain halogenated solvents, the VOC content may be used as a surrogate for HAP content in coatings and has added the clarifying information to 40 CFR 63.750( c), (d), (k), and (l). The EPA has also added language to clarify that, unless stated oth erwise on the manufacturer’s documentation, the VOC content is assumed to be less wa ter and exemption solvents.

As also previously explained in order to verify the HAP co ntent of such coatings, the EPA is also adding EPA Method 311, Analysis of Hazardous Air Pollutant C ompounds in Paints and Coatings by Direct Injection Into a Gas Chromatograph, to 40 CFR 63.750 as the EPA reference method to confirm the HAP content of coatings. In the e vent of any inconsistency between the EPA Method 311 test data and the manufacturer's supplied for mulation data, that is, if the EPA Method 311 value is higher, the EPA Method 311 test will gove rn unless after consultation, the75

facility can demonstrate to the satisfaction of the e nforcement agency that the formulation data

were correct.

However, the EPA disagrees with the commenter that f acilities should not be subject to enforcement action if laboratory testing reveals a value over the limit when the manufacturer data shows values that are compliant and no additional solvents were added by the facility. If the EPA adopted the commenter’s recommendation, then the E PA would have no method to enforce

the VOC and HAP content standards in cases where a coa ting applicator adds HAP containing solvent to the coating. Laboratory testing of the VOC a nd HAP content of coating samples collected in an “as applied” condition using EPA Methods 24 (for VOC) and 311 (for HAP) is needed to ensure compliance with the requirements of surf ace coating NESHAP and to ensure that coatings are not in violation due to excessive HAP c ontaining solvent added by the coating applicator.

Comment: One commenter (0830-0030) was opposed to allowing facilities to rely on coating manufacturer's supplied information, regardless of the am ount of emissions, because it would be unlawful and arbitrary. The commenter argued that authorizing sources to avoid any emission testing to assure compliance would violate the Act’s requi rement that standards apply at all times, and the requirement that emission limits and pe rmit limits be sufficient to assure compliance. 84 The commenter explained that this is arbitrary and capri cious because EPA has not

shown that such documentation is reliable or a reasonabl e substitute for an actual compliance demonstration in regard to a source’s actual emissions. T he commenter argued that EPA has not shown (1) test data showing that the manufacturer’s data product sheets indeed match the air emissions; (2) how such “supplied formulation data” could “ indicate” that coatings meet the standards; (3) how other factors, such as the amount of co atings, the use of different kinds of coatings, the application of coatings, and other steps in the maintenance and use of equipment would not possibly affect the amount of actual HAP emiss ions in the air; and (4) how it will prevent inaccurate manufacturer documentation from circ umventing the emission limits.

The commenter argued that a coating manufacturer’s product supply document is insufficient to assure compliance because it may be outdated or inaccurat e and may not actually reflect the amount of HAPs or VOCs in a coating. Instead, to ensure so urces actually comply with emission limits, the commenter recommended that EPA must require the regulated sources themselves to test, report, and keep records on their actual HAP emiss ions.

The commenter argued that manufacturers are not subject to the emission limits and EPA has not

outlined how an enforcement action for a false HAP/VOC -content report could be brought to give them incentive to ensure accuracy of their document ation. To the contrary, knowing that they are more likely to be able to sell more product if t hey submit documentation that says the HAP/VOC content limit is below EPA’s standards will pro vide more incentive for them to do so – regardless of the actual content, and without appropriate quality control to assure all of their product indeed meets the specifications. The commenter ar gued that even if the content is accurate, a facility may be using it incorrectly or emis sions may be combining to increase the

84 42 U.S.C. § 7602(k); id. § 7661c(a) and implementing regulations.76

actual HAP content in the air above the levels of the standards and EPA has not shown how relying only on this will assure compliance with the emissi on limits.

The commenter stated that this would create significant enforcement problems for EPA, states, and affected community members because the requirement to avoid HAP emissions falls on sources regulated under the Clean Air Act, not coating manu facturers. The commenter added that

if a source retains documentation from a manufacturer t hat does not reflect the correct HAP emissions, that source may continue emitting HAPs no m atter how high its actual emissions may be. The commenter argued that community members will hav e no information to be able to assess whether, in fact, a source’s emissions meet t he standards and would make it impossible

for communities to receive relief if emissions were hi gher than predicted by manufacturer's

documents. It is unclear to the commenter how EPA or sta tes could assure this either. The commenter opposed finalizing provisions that will, by default , exempt emissions from the limits, no matter how much HAP they put into the air of nearby c ommunities.

Response: The EPA disagrees with the commenter that more test ing of coating should be required and that facilities should not be allowed to use coating manufacturer’s documentation to demonstrate compliance. The EPA has included the use of co ating manufacturer's formulation data to demonstrate compliance with HAP and VOC content limits in numerous surface coating NESHAP. The EPA has not experienced the enforcement is sues described by the commenter as a result of this approach.

The EPA has compared emissions predicted from coating m anufacturer's product data sheets with measured emissions. As part of developing the risk model ling database for the residual risk analysis for this source category, the EPA requested tha t certain facilities also test their air emissions from surface coating operations. 85 These data showed that the air emissions were no higher than the emissions that were estimated from the coating manufacturers' product data sheets, and coating manufacturers' product data sheets, in fact, tended to significantly overstate the emission potential of the coatings.

This testing has also shown that other factors, such as the amount of coatings, the use of different kinds of coatings, the application of coatings, and othe r steps in the maintenance and use of application equipment do not affect the amount of actual HAP emissions in the air in such a way that they would exceed the HAP emissions estimated fro m the coating manufacturer's

formulation data.

Even though coating manufacturers are not the entities t hat must comply with subpart GG, they still have many economic and regulatory incentives to pro vide accurate information on the VOC and HAP content to their customers. Coating manufacturer s are required by Occupational Safety and Health Administration (OSHA) regulations to provide a Material Safety Data Sheet (MSDS) for each coating they manufacture. These MSDS are requi red to show the hazardous constituents of those coatings, and as part of the hazard communicat ion to their coating users, many coating suppliers are also indicating the regulatory VOC level of the coatings (i.e., grams VOC per liter of coating less water and exempt solvents). Some manufa cturers are also providing the HAP

85 See the memorandum, Aerospace Manufacturing and Rework Fac ilities RTR Modeling File Preparation, in docket EPA-HQ-OAR-2014-0830.77

content. Coating manufacturers have a strong incentive to ensure that this information is accurate because they know that their customers will be using it to demonstrate compliance, and they know that the EPA also has the authority to test samp les of coatings using EPA methods 24 (Determination of Volatile Matter Content, Water Con tent, Density, Volume Solids, and Weight Solids of Surface Coatings) and 311 (Analysis of Hazardous Air Pollutant Compounds in Paints and Coatings by Direct Injection Into a Gas Chromatograph) . Coating manufacturers are likely to face civil lawsuits and the loss of business if they provide faulty documentation that results in an EPA violation for one of their customers. They may al so face enforcement by OSHA if it is

shown that MSDS included inaccurate information on hazardous constituents in coatings.

Finally, the EPA can still inspect aerospace manufacturi ng facilities to collect samples of coatings and test them to measure the VOC and HAP cont ent to compare them to the

manufacturer’s documentation of the VOC and HAP content , and other records kept at the facility. In addition, many state and local air pollutio n control agencies that have VOC content limits for aerospace coatings that are the same as th e VOC content limits in subpart GG perform compliance testing.



### 11.0 Other Emission Sources Not Currently Regulated

Comment: One commenter (0830-0030) argued that the EPA must set emiss ion standards for all other currently uncontrolled emission points in the aer ospace source category. The commenter noted that EPA argued in 1994 that control of organic HAP emi ssions from the four non-coating related operations that are uncontrolled (chemical milli ng, metal finishing, electrodeposition, and composite processing) was “not feasible because no demons trated control measures could be

identified.” 86 However, the commenter argued that EPA has a “clear st atutory obligation to set

emission standards for each listed HAP” 87 regardless of whether the best-performing sources in a given category are currently using air pollution control technology to limit their emissions. 88
The commenter argued that the Agency must regulate emissio ns from all the emission points that are part of the affected source. The commenter disagreed with EPA’s claims about the relative significance of HAP emissions from the four non-coatin g-related operations, and the agency’s failure to identify control measures cannot justify faili ng to set emission standards for these operations. The commenter concluded that EPA must set st andards for these currently uncontrolled sources for the same reason that it is pro posing to set standards for specialty coating operations.

The same commenter argued that EPA lacks authority simp ly to declare that sources of HAP emissions are not worth controlling 89 even if emissions from a non-coating operations consti tute less than 1 percent of the total organic HAP emissions f rom aerospace facilities.

The commenter added that EPA has failed to regulate three coating-related operations: adhesives, adhesive bonding primers, and sealants. Accordi ng to the commenter, EPA previously

86 59 Fed. Reg. 29,216, 29,239 (June 6, 1994) (“1994 Proposed Rule”).

87 Nat’l Lime Assn. , 233 F.3d at 634.

88 Id.

89 Id.78

argued that the organic HAP emissions from these processes are “relatively small” and that many of the coatings in use are already applied using efficie nt techniques, and thus there was little

room to reduce emissions further. 90 EPA discussed the possibility of using coatings with lower organic HAP content, but asserted that it lacked data on o rganic HAP content of coatings at the time of the proposal, and it did not have time to collec t any, according the commenter. The commenter argued that as EPA has shown for specialty co atings – emissions are quite large from that type of emission point (360 tpy from that subset of the source category alone), which suggests other uncontrolled emission points may also have substantially more emissions than EPA had previously believed. The commenter pointed that E PA has collected some new data on emissions from the source category that should allow it to address the other operations that are currently uncontrolled in the same way that it is prop osing to set standards for specialty coating operations.

The commenter stated that EPA must set emission standa rds for each HAP emitted by a source category to satisfy its responsibility under CAA § 7412 a nd therefore, cannot fulfill its obligation by setting standards for some parts of the source categor y and not others. The commenter argued

that EPA must evaluate new data that were collected a nd set standards that close significant gaps in the standards for this source category and thus lack o f data on the effects of non-technology

factors on emissions cannot excuse the failure to set a floor. 91

Response: We disagree with the commenter that the EPA is requi red to establish standards for the four operations cited by the commenter (i.e., chemic al milling, metal finishing, electrodeposition, and composite processing). This is beca use they are not part of the surface coating source category regulated by the Aerospace Manufa cturing and Rework NESHAP. In the initial list of categories published in 1992 and the revised l ist published in 1996, the EPA identified Aerospace Manufacturing and Rework Facilities a s a “surface coating source category.” 92 Chemical milling, metal finishing, and electrodeposition are not part of the Aerospace Manufacturing and Rework surface coating source c ategory and are not unique to aerospace manufacturing facilities. For example, at ar ea sources, but not major sources, these operations are regulated by subpart XXXXXX, the NESHAP f or Nine Metal Fabrication and Finishing Area Source Categories. Composite processing at major sources is regulated by subpart WWWW, the NESHAP for Reinforced Plastic Composi tes Production.

Comment: One commenter (0830-0028) agreed with the EPA’s decision to not regulate additional emission sources (chemical milling, metal fi nishing, waste water, storage tanks, and composite operations) because they are not surface coati ng operations and are outside of the source category, based on the CAA Section 112(c)(1) listi ng of categories and subcategories of major sources of HAP. The commenter noted that in both the initial list of categories published in 1992 and the revised list published in 1996, EPA identified Aeros pace Manufacturing and Rework Facilities as a “surface coating source category. ”

Response: The EPA acknowledges the commenter’s support.

90 1994 Proposed Rule, 59 Fed. Reg. at 29,239.

91 Sierra Club , 479 F.3d at 882.

92 Final Report: Documentation for Developing the Initial Sour ce Category List, EPA-450/3-91-030; (July 1992)79



### 12.0 Estimated Cost, Economic, and Environmental Impacts

Comment: One commenter (0830-0028) contended that the proposed rule does not provide a detailed explanation of the basis for EPA’s finding tha t the proposed action is not a significant regulatory action and, therefore, was not submitted for re view by the Office of Management and Budget (OMB) as an action having an annual effect on the economy of $100 million or more, as required by Executive Order 12866. The commenter stated that this detailed explanation was likely not provided because EPA greatly underestimated the total annual cost of the proposal at $590,000. The commenter noted that, as a significant regulatory action, the EPA would also be required to include more detailed underlying assessments of the costs and benefits of the proposed action and potentially effective and reasonably f easible alternatives as well as provide information about the regulatory action to the Office of Information and Regulatory Affairs.

Response: The EPA disagrees with the commenter that the EPA did not provide a detailed explanation of the basis of the cost and burden estimat es. The EPA’s detailed costs and burden

estimates were documented in the items that are included i n the docket for this rulemaking. The cost estimate methodology and assumptions are included in the memo, Estimated Cost Impacts for Proposed Amendments to 40 CFR 63, Subpart GG, National Emission Standards for Aerospace Manufacturing and Rework Facilities (docket item EPA-HQ-OAR-2014-0830-0005) and the burden estimate under the Paperwork Reduction Act a re included in the Aerospace NESHAP Risk and Technology Review Information Collection Request Supporting Statement and

Tables (docket item EPA-HQ-OAR-2014-0830-0009).

The EPA also disagrees with the commenter’s assessmen t that the cost impacts of the final rule would have an effect on the economy of $100 million or mor e, and that the rule should be submitted to the OMB for review, as required by Executive Or der 12866. As explained in the responses to the more detailed comments, below in this se ction, even if the EPA accepts the commenters estimates’ of the costs for complying with subpart GG and applies them to EPA’s estimate of the number and size of facilities with spe cialty coating operations, the costs are well below the $100 million threshold for OMB review.

Comment: Two commenters (0830-0027, 0830-0028) argued that the EPA did not acco unt for the cost of reformulating coatings and bringing new produc ts to market to comply with the proposed organic HAP and VOC limits, and the costs account only for recordkeeping and reporting costs. One commenter (0830-0027) argued that although s pecialty coatings that meet the CTG limits exist, the CTG has not been widely adopt ed and not all coating manufacturers sell coatings in the market areas that are subject to specialty coating limits based on the CTG. The commenter argued that because specialty coatings are used in smaller volumes, the cost to reformulate and test compliant coatings is higher per unit than for higher volume coatings. The commenter added that compliance with the performance sp ecifications for aircraft, and for compliance with other regulatory programs, such as OSHA, adds other layers of testing and cost to reformulation that have not been accounted for by EPA

.

One commenter (0830-0028) noted that of the two-thirds (74) of the facilities using specialty coatings that will be required to take actions to comply with the proposed organic HAP and VOC standards, it is likely that some of these facilities will need to find replacement coatings or reformulate current coatings. The commenter stated tha t the approval process for replacement80

coatings is lengthy and costly and may reach $1 million pe r coating. The commenter stated that reformulating and implementing new coatings in cases w here no replacement coatings are available may be as high as $5 million to $10 million per s pecialty coating, depending on the coating type and level of testing. The commenter added tha t recent experiences with replacing obsolete specialty coatings demonstrate that suppliers ma y not be willing to spend resources reformulating small volume specialty coatings with dema nding technical requirements and that fewer coating manufacturers are willing to certify confor mity to aerospace specifications and submit their products to the aerospace industry’s lengthy and expensive inspection and testing process. The commenter suggested costs to replace or refor mulate specialty coatings could be significantly reduced if EPA provides a mechanism to approve these coatings that do not meet the proposed standards. The commenter added that costs for low volume and highly specialized formulations would be reduced by providing an additional 200 gall ons to the total volume of coatings that may use the low volume exemption.

Response: The EPA disagrees with the commenter that the EPA un derestimated the cost impact of the proposed rules. The commenter did not provide any dat a on specific specialty coatings that could not meet the proposed VOC content limits or to suppor t an estimate of the number of coatings that would need to be reformulated to comply with the proposed limits.

In the absence of any specific data from the commenter s to demonstrate otherwise, the EPA still believes that compliant coatings are available for a ll applications in all of the specialty categories and that these compliant coatings are likely to already be certified or approved to meet current performance standards for those coatings.

The EPA has estimated that the vast majority of the specialty coatings in use already meet the proposed HAP content limits, based on both the number o f coatings used and on the volume of coatings used. The EPA received data from the 2011 ICR that allowed the EPA to estimate the HAP content of 5,173 specialty coating “applications.” For this analysis, an “application” represents one row of data from the ICR and generally r epresents one specialty coating reported at one facility; some specialty coatings were reported at multiple facilities, and some facilities reported the same coating multiple times to represent ea ch operation using that coating; in the latter case, each operation would represent one applicat ion. The EPA estimated the HAP content in units of grams of HAP per liter of coating because t he EPA did not have data to correct the HAP content to g/liter less water, but very few of t hese coatings are believed to be waterborne

formulations.

Of the 5,173 coating applications for which the EPA was abl e to estimate the HAP content, about 96 percent of coating applications, also representing about 96 percent of coating volume, were already below the proposed HAP content limits. The EP A estimated that only 225 coating applications were non-compliant. The EPA found no cases in which all the coatings in a specialty category (even in those categories with very few coatings reported) were noncompliant. For 75 of the non-compliant applications, the manufacturer and the product were not reported, so the EPA could not determine if these were duplica tes of other coatings. Finally, some of the non-compliant materials were thinners, ac tivators, or other types of additives that are not used as coatings by themselves, but would be mixed with o ther components to form the complete coating and would then likely have a lower HAP c ontent.81

Comment: One commenter (0830-0028) stated that EPA underestimated the effort required to determine coating content of specialty coatings and there fore the proposed ICR estimates are very low and fundamentally incorrect. The commenter not ed that there are costs that EPA did not take into consideration and EPA should adjust its cost e stimates accordingly.

The commenter stated that EPA’s estimate of one hour per coating may be reasonable for coatings where the manufacturer supplies all the needed da ta in the proper format and the facility can rely on the data to demonstrate compliance, but whil e manufacturers commonly supply VOC content in the same format as the proposed VOC limit, total HAP content is either rarely provided or is often expressed as a range of the percent we ight of HAP compounds or as an “up to” amount. The commenter stated that demonstrating com pliance could be time-consuming and burdensome because in these situations a facility would ne ed to perform multi-step calculations to convert the manufacturer’s HAP content into the pro per units or perform additional laboratory analyses. The commenter noted that some percentage of t he coatings must be assumed to require data gathering beyond already available information and th ese additional costs should be included in the ICR analysis and burden analysis. The comm enter suggested that EPA could reduce burden for coating content determinations by clarifyi ng that facilities can definitively rely on coating manufacturer VOC data and use VOC content as a surrogate for organic HAP content for coatings that do not contain exempt solvents that are also HAP.

The commenter also stated that the current provisions which require facilities to calculate coating VOC content using formulas or laboratory analyses are being retained as the base compliance option and therefore costs for this should have been e stimated in the ICR but do not appear to have been. The commenter argued that EPA is effective ly basing its entire analysis on the alternative compliance option, but cannot assume that facilities will not use the base compliance approach.

The commenter estimated that performing content calcula tions, requesting additional information from manufacturers, and performing analyses would require 5 to 10 hours of labor per specialty coating, plus analytical service fees of $575 per coating (fo r VOC content by Method 24) and a minimum of $3,000 per coating (for HAP content by Method 311).

The commenter also questioned EPA’s assumption of approxim ately 30 coatings per facility, stating that this underestimates burden at larger facilit ies as they typically use approximately 200 to 1,000 specialty coating formulations.

The commenter also noted that when manufacturers make c hanges to coating compositions or otherwise update their documentation, the coating content calculations and analyses for the base compliance option need to be repeated and/or verified by th e facility and computer systems will need to be updated to reflect new data for the alternative compliance option.

Response: As noted in the response to the previous comment, the E PA does not believe that the compliance costs have been underestimated. As noted by t he commenter, the EPA is allowing facilities to use the coating manufacturer’s VOC conten t determined from formulation data to demonstrate compliance with the HAP content limits fo r coatings that do not contain the exempt solvents that are also HAP. For coatings that contai n exempt solvents that are also HAP,82

facilities can use the coating manufacturer’s documenta tion of the HAP content based on coating formulation to demonstrate compliance.

The EPA did not estimate the compliance costs based on the other compliance calculations and analytical methods in the rule because the most likel y compliance option for the vast majority of coatings used by facilities is to use the manufacturer’s documentation of HAP or VOC content for each coating.

However, if one were to make a “worst-case” assumptio n that the industry would need to perform EPA Method 24 testing for 5,000 coatings in one year (based on the approximate number of specialty coatings reported in the 2011 ICR), and a ssumed that facilities needed 7.5 hours of labor at a cost of $100 per hour to perform calcul ations and arrange for VOC testing, and a cost of VOC testing of $575 per coating, the total cos t for the industry in that one year would be about $6.6 million. These costs would not be annual costs because facilities would not have to test that many new coatings in any one year.

The EPA identified only 45 coatings being used at 21 facilitie s that contained HAP that were not

VOC. If one assumed that facilities needed 7.5 hours of l abor at a cost of $100 per hour to perform calculations and arrange for HAP testing, and a cost of HAP testing of $3,000 per coating, the total cost for the industry in that one y ear would be about $170,000. These costs

would not be annual costs because facilities would not ha ve to test that many new coatings in

any one year.

The EPA agrees with the commenter that larger facilit ies may use more specialty coatings than an average of 30 coatings per facility. However, the tot al burden and cost impact estimated by the EPA did not use the 30 coating per facility average, but instead used the actual number of specialty coatings reported per facility in the 2011 ICR. The 30 coatings average is just that, an average that is useful for estimating impacts to the “a verage” facility.

Because the EPA expects that facilities will use the manufacturers’ documentation of the VOC or HAP content to demonstrate compliance, that documenta tion will most likely be updated by the coating manufacturers and provided to the facilities with pur chases of any reformulated coatings. Therefore, it is unlikely that facilities will need to re peat or update the compliance calculations.

Comment: One commenter (0830-0028) stated that the tracking of coatin g usage and maintaining records for compliance imposes significant i nitial capital and labor costs as well as ongoing labor burdens. The commenter argued that EPA’s esti mate of 27 labor hours per facility in the initial year and no capital expenses is incorr ect and unsustainable. The commenter disagreed that all facilities will use existing tracking s ystems because, while aerospace facilities that are currently subject to state and regional specialt y coating regulations may have tracking systems, the majority of facilities (approximately 74) do not and therefore must design, purchase, and install a system. In addition, the commenter furthe r noted that due to the large number and variety of applications for specialty coatings, the exi sting systems for primers and topcoats may not even work and will either need to be modified or repl aced.83

The commenter explained that tracking systems for speci alty coating application operations are far more complex and expensive than systems developed to tr ack other coating applications at aerospace facilities or in other surface coating source categories.

The commenter noted that many facilities will expend a considerable amount of effort to identify all the materials they use that EPA would consider a spe cialty coating because this proposal includes in the specialty coating definition a wide variet y of previously unregulated materials that are applied outside of spray-coating booths and hangars. The facilities must then identify current and potential uses of each specialty coating an d determine if the coating meets the standard for each applicable classification. The commen ter further noted that additional tracking is necessary if a single coating is used in more than o ne classification, which is different than other EPA coating standards which have at most six coat ing classifications and also different than the current primary and topcoat standards which provide a limited number of content

restrictions that are easier to track.

The commenter stated that a facility must also continuo usly track use of specialty coatings to ensure each coating is used only for applications for which it meets the applicable limits. This could require expansion of material control protocols and worker training. In addition, the commenter noted that the tracking of coatings may have to reach the individual part level, adding a further level of complexity to the tracking system.

The commenter stated that to accommodate complex trac king, facilities would have to purchase or invest in upgrades to existing systems to monitor and cont rol purchasing and use of specialty coatings. These systems would be in addition to existi ng purchase controls because those systems do not track internal deliveries to specific specia lty coating operations; these systems must be integrated across departments to ensure that appropr iate coatings that meet the content limits are included in the aircraft design, are purchased, and are used for the appropriate applications.

The commenter stated that the initial capital costs a nd labor to purchase and install these systems will be significant, as will the operating labor costs because any type of tracking system will require labor and training to maintain and audit. The comme nter further noted that these costs are significantly higher than for a system to track just prim ers and topcoats as that focuses on just the paint shops.

The commenter stated that larger facilities in Souther n California had costs of $5 to $7 million as they implemented systems for daily compliance/trackin g, and argued that these were similar to costs for several facilities in other states subject to specialty coating regulations. These costs include up to $1.5 million to purchase a tracking software sy stem and for labor costs to implement the system and train employees. The comment er argued that annual costs going forward will decrease but will still involve ongoing softwa re and labor costs and that one California facility with daily tracking requirements es timated costs at $3 million per year. The commenter concluded that because many aerospace facilitie s are not currently subject to state or regional specialty coating regulations, their expected c osts would be similar to these example costs. Although these estimates are from facilities w ith daily tracking requirements, the commenter stated that the burden to track specialty coat ings in accordance with the annual/monthly requirements in the proposed rule vastly ex ceeds EPA’s 27 hour estimate.84

Response: The EPA disagrees with the commenter. The costs for a facility complying with daily tracking for all coating operations are not comparable to nor representative of the costs of complying with the subpart GG amendments to add specialty coatings. First, subpart GG does not require daily tracking of coating usage for any complia nce option, and the final rule will only require monthly tracking if a facility is using the ave raging provisions. Otherwise, only annual tracking of consumption is required, and this can be accomp lished through the use of annual purchase records. Second, the amendments would add only requi rements for specialty coatings, whereas most facilities are already complying with requir ements for primers and topcoats.

The EPA also disagrees with the commenter that coatin g use would need to be tracked continuously or to the level of the individual part. Nea rly all of the specialty coating categories are defined by the functional characteristics of the coa ting, and only a few coatings (e.g., rocket motor nozzle coatings and fuel tank coatings) are defined by the types of parts to which they are applied.

The costs reported by the commenter are also for larger facilities and are not expected to be representative of the majority of facilities that wo uld need to begin tracking specialty coatings. The commenter reported that the larger facilities for which they cited costs use 200 to 1,000 specialty coating formulations, whereas the average faci lity reported to the EPA in the 2011 ICR using only 30 specialty coatings per facility. Therefore, ev en if new tracking systems are needed for some facilities, their capital and annual costs ar e likely to be one to two orders of magnitude (that is, 1/10th to 1/100 th ) of the costs reported by the commenter. This is esp ecially true given that the complexity of tracking systems is likely to gro w exponentially at larger facilities as the number of coatings and coating operations increase at a facility, subpart GG does not require daily coating usage tracking and, in the final rule amendme nts, requires monthly coating usage tracking only if the facility is using the averaging provisi ons.

If one assumes that the costs for tracking specialty coatings at a facility using an average of 30 specialty coatings were 1/10 th of the capital and annual costs cited by the commenter a large facility and applied them to the 74 facilities using specialt y coatings that are not already subject to a VOC rule based on the CTG, the total industry costs ar e much lower than implied by the commenter. For 74 facilities, assuming a capital cost o f $150,000 and annual costs of $300,000, the total capital costs would be $11.1 million, and the annua l costs would be $22.2 million.

Comment: One commenter (0830-0028) stated that EPA’s assumption that costs of upgrading high-efficiency application equipment for specialty coa tings will be completely offset by reductions to the amount of coating used is incorrect for m any facilities where changes to the manufacturing process to accommodate this equipment will more than offset savings from reduced paint use. The commenter noted that, based on EPA’s understanding that 11 California facilities are already required to meet these equipment standards, 98 of the 109 facilities affected by this new requirement may need to purchase or upgrade equi pment and adjust manufacturing processes to comply, which results in a significant cost to industry. The commenter added that although the cost of new HVLP equipment and training may e ventually be offset by savings in coating usage, for many applications HVLP is not the mos t efficient application method and it is very unlikely that the cost offsets identified by EPA w ill be achieved.85

Response: The EPA disagrees with the commenter’s interpretatio n of the EPA cost estimates for high efficiency application methods. The EPA cited the fact that 11 California facilities are already required to meet requirements for high efficiency application methods for specialty coatings as the basis for establishing these as MACT fo r applying specialty coatings. In the cost memo in the docket (docket item EPA-HQ-OAR-2014-0830-0005), the E PA did not estimate the actual number of facilities that would need to upgrade their application equipment, but only estimated the cost impact and savings for an average fa cility based on the information in the ICR. In the cost memo, the EPA noted that many facilit ies have already likely switched to high efficiency application methods for economic reasons th at were illustrated by the analysis in the

cost memo.

The EPA agrees with the commenter that HVLP spray guns a re not the most efficient application method for certain coating operations and, as result, ha s adopted many of the commenter’s recommendations into the final rule requirements relat ed to the application of specialty coatings. These changes are described in the section on “Specialt y Coating Application Equipment Requirements” in this document.

Comment: One commenter (0830-0028) stated that EPA’s cost estimate excludes costs for the installation, expansion, or upgrade of paint booths to accomm odate spray-applied specialty coating operations. The commenter explained that although the majority of specialty coating operations may be conducted in booths controlled by filter s meeting the proposed standards, this is not true for all specialty coating spray application operations. The commenter argued that requiring all of these operations into spray booths, parti cularly operations already well controlled by alternate work practices and equipment, would result i n significant costs across the aerospace industry. The commenter urged EPA to consider including costs f or installing new booths or upgrading or expanding existing booths to accommodate all specia lty coating operations that contain inorganic HAP to meet the proposed requirements in Section 63.745(g)(2)(ii)(A). The commenter added that a new booth with a filtration syst em meeting these requirements for new sources costs approximately $400,000 (including $250,000 for the booth and $150,000 for labor) and may range much higher depending on the booth size.

Response: The EPA did not include costs for additional spray booths for specialty coating operations because the EPA assumed that specialty coati ng operations that were not already performed in spray booths would be able to use spray booths t hat were already present for primer and topcoat application operations. Even if there are spr ay-applied specialty coating operations that cannot use existing primer and topcoat spray booths, the EPA believes that the spray booth requirements for specialty coating operations will have a minimal cost impact on aerospace facilities for several reasons. First, the EPA has revised the spray booth requirements that apply to all coating operations, based on public comments, to cla rify that the use of portable enclosures that meet the same filtration requirements as for sp ray booths can be used to comply. Second, the spray booth requirements apply only to the spray applicatio n of coatings that contain inorganic HAP, and fewer than 10 percent of all the specialty coat ings reported in the 2011 ICR (including those that are spray and non-spray applied) contained inor ganic HAP. Finally, spray applied coating operations that are of sufficient size to requ ire the construction of the spray booth described by the commenter (for example, greater than on e gallon of coating spray applied in an 8-hour work period) are already being required to be in a s pray booth to comply with OSHA regulations to minimize worker exposure and to prevent fire s (see, for example, 29 CFR86

1910.107 and National Fire Protection Association standard 33, whi ch both address spray finishing using flammable and combustible materials). Given these factors, the EPA believes that the cost for additional spray booths as a result of the rules for specialty coating operations is expected to be minimal.

Comment: One commenter (0830-0028) argued that compliance costs can b e reduced if EPA minimized the requirement for monthly records of coatin g usage. The commenter noted that the current rule requires facilities to maintain records of the volume of each coating formulation used each month, and the proposed rule changes to 40 CFR 63.752(c) and (f) would allow facilities to use annual purchase records only if they are using manufactur er’s documentation of the VOC or HAP content. The commenter argued that keeping the requirem ent to keep monthly usage records for any coating not used in an average places an u nnecessary burden on facilities to track the volume of these coatings used at each operation and does not meet the Paperwork Reduction Act requirement to require collection of only information that “is necessary for the proper performance of the functions of the Agency, including wheth er the information shall have practical utility.” 93 The commenter argued that the monthly volume of coati ng used is irrelevant to the compliance demonstration if the facility is us ing records of which coatings are used and the VOC and HAP content of the coatings, and are only needed if the facility is using the averaging provisions. The commenter argued the rule should be revised so that all facilities that are not using averaging should be required to maintain only a nnual purchase records instead of monthly usage records.

Response: The EPA agrees with the commenter and is revising the re quirements in 40 CFR 63.752(c) and (f) to require monthly usage only if the coatings are being averaged. The EPA agrees that monthly usage records are only needed if avera ging is being performed. Otherwise, none of the compliance demonstration requirements uses m onthly coating consumption and a record of annual consumption of each coating is suffici ent.

Comment: One commenter (0830-0028) argued that EPA can reduce the recor dkeeping and reporting burden by requiring that all coating manufacturers supp ly the information necessary to demonstrate compliance using manufacturer supplied data. The c ommenter argued that market forces are not sufficient to cause all coating manufact urers to provide the VOC content on their documentation, especially small manufacturers of special ty coatings that may not have been subject to VOC regulations. The commenter argued that the EP A should require all coating manufacturers to provide VOC content data, as grams per liter (less water and exempt solvents), under EPA’s authority to request air emissions informatio n under section 114 of the CAA and provide that data on the product label, product data sheet, or MSDS.

The commenter argued that Section 114 of the Clean Air Ac t provides the Agency the authority to require coating manufacturers to provide coating contentdata. Under Section 114, “[f]or the purpose” of “carrying out any provision of this chapter,” the Agency may require “any person ... who the Administrator believes may have information necessary for the purposes set forth in this subsection,” to “provide such other information as the Adm inistrator may reasonable require.” The commenter argued it is also reasonable for EPA to r equire coating manufacturers to supply these data because these companies have ready access to these data as the manufacturers of the

93 44 USC § 3508.87

coatings, and could provide it at minimal cost, compared to the cost to the regulated industry to determine the VOC content through testing.

Response: The EPA agrees that the burden on aerospace facilities would be reduced if coating manufacturers provided VOC or HAP content documentation that met the compliance needs of the aerospace facilities. However, the EPA does not ha ve the authority under CAA Section 114 to compel the coating manufacturers to provide that informat ion to the aerospace facilities in the form of information on product labels, product data sheets, or MSDS so that information could then be provided by aerospace facilities to EPA for compli ance purposes.

As previously explained, coating manufacturers are required by Occupational Safety and Health Administration (OSHA) regulations to provide MSDS for ea ch coating they manufacture. These MSDS are required to show the hazardous constituents of t hose coatings, and as part of the hazard communication to their coating users, many coating suppliers are also indicating the regulatory VOC level of the coatings (i.e., grams VOC per liter of coating less water and exempt solvents). Some manufacturers are also providing the HAP content. We believe coating manufacturers have a strong incentive to ensure that thi s information is accurate because they know that their customers will be using it to demonstrate compliance, and they know that the EPA also has the authority to test samples of coatings using EPA methods 24 (Determination of Volatile Matter Content, Water Content, Density, Vo lume Solids, and Weight Solids of Surface Coatings) and 311 (Analysis of Hazardous Air Pollutant Com pounds in Paints and Coatings by Direct Injection Into a Gas Chromatograph).



### 13.0 Technical Corrections

Comment: One commenter (0830-0027) provided the following technical cor rections:

§ 63.750 Test methods and procedures. (k) Organic HAP content level determination–compliant chemical milling maskants

(k)(2) [Reserved]

With the clarifications within 40 CFR 63.750(k), the commente r suggested that paragraph (k)(2)

should be deleted.

§ 63.753 Reporting requirements. (c) Primer, topcoat and specialty coating application operations

Each owner or operator of a primer or topcoat application....

The commenter suggested modifying this language to read: “Each own er or operator of a primer, topcoat, or specialty coating application....” to clarify that this sec tion applies to specialty coating applications.

Response: The EPA acknowledges that with amendments being made to 40 CFR 63.750(k), this ma y seem to be a convenient time to remove reserved paragraph (k)(2). However , the EPA is making no other changes to 40 CFR 63.750(k), so the EPA is keeping the placeholder fo r paragraph (k)(2) to maintain the current paragraph numbering of this section.88

The EPA agrees with the change to 40 CFR 63.753(c) and has made that ch ange in the final rule.

Comment: One commenter (0830-0028) requested that EPA change specialty coating “Corrosion Prevention System” in Appendix A of subpart GG to “Corrosion Prevention Compound” to match the naming convention used in Table 1.

Response: The EPA acknowledges this difference within subpart GG, but in the final r ule is changing the name used in Table 1 to match the category definition in Appendix A because that definition specifically uses the word “system,” instead of “compound,” in the body of the definition.

Comment: One commenter (0830-0028) stated that monitoring of dry partic ulate filters, HEPA filters, and waterwash systems should only be required duri ng spray-application of coatings containing inorganic HAP. The commenter noted that because the inorganic HAP standards in Section 63.745(g) apply only to the spray-application of coatin gs with inorganic HAP, the EPA should clarify that these monitoring provisions are only required once per shift when primer, topcoat, or specialty coatings containing inorganic HAP are being spray-applied.

Response: The EPA did not propose any changes to the filter monito ring requirements in 40 CFR 63.745(g)(2)(iv) and (v). Therefore, the EPA did not, th rough this rulemaking, reopen the opportunity for comments on previous actions taken and EPA considers these comments as beyond the scope of today’s action.

Comment: One commenter (0830-0028) noted that EPA should state in Se ction 63.752(a) that facilities are not required to keep records in accordance w ith Section 63.10(d)(5), to be consistent with the removal of startup, shutdown, and malfunction re quirements in Section 63.753(a) and Table 1 of subpart GG.

Response: The EPA agrees and has added 40 CFR 63.10(d)(5) to the list of pa ragraphs in 40 CFR 63.10 that do not apply.

Comment: One commenter (0830-0028) noted that the term “affected unit” should be changed to “affected source” in Sections 63.752(a)(1) to (3), for con sistency with other sections of the

rule.

Response: The EPA agrees and has made that change.

Comment: One commenter (0830-0028) requested that EPA correct Table 1 o f subpart GG to indicate that Sections 63.10(c)(7) and (8) are not applicable to the Aerospace NESHAP because subpart GG does not require continuous monitoring systems.

Response: The EPA disagrees that subpart GG does not require contin uous monitoring systems. If a facility uses an add on control device for controll ed coating operations, continuous monitoring may be required, such as temperature monitoring f or combustion devices as specified in 40 CFR 63.751(b)(6) through (b)(12).

Comment: One commenter (0830-0028) requested that EPA clarify in the final rule if Sections 63.10(b)(2)(vii) to (xiv) are applicable to the Aerospace NESHAP

.89

Response: The EPA acknowledges that in the version of Table 1 to s ubpart GG published in the Federal Register (80 FR 8438), the row for 40 CFR 63.10(b)(2)(vi i) to (xiv) in the amended Table 1 to subpart GG was inadvertently left blank in the second column, and this should have been marked “Yes” that these requirements still apply. The amendments to Table 1 changed only certain elements in Table 1 and those changes were expl ained in the preamble. Before the amendments, all of paragraph 63.10(b) applied to subpart GG. S ub-paragraphs 40 CFR 63.10(b)(2)(vii) to (xiv) are not being amended, and they still apply to subpart GG.



### 14.0 Comments Outside the Scope of the Proposal

Comment: One commenter (0830-0029) argued that EPA Method 319, Determin ation of Filtration Efficiency for Paint Overspray Arrestors, does not accurately predict the real world efficiency of paint overspray arrestors to filter out c hromate paint particles from facility exhaust emissions. The commenter argued that the lack of accurac y is due to the fact that the filtration efficiency is measured using potassium chloride and oleic oil p articles instead of actual paint overspray particles. The commenter argued that in some c ases, the fractional efficiencies of 3- stage filter systems using paint overspray were nearly 80 pe rcent lower in the micro-particle size ranges compared to those obtained from Method 319. (The co mmenter did not provide any supporting data or test results.)

The commenter argued that the EPA’s Environmental Technolo gy Verification program mandates the use of only the most advanced and credible te chnologies in the development of standards and regulations, and that the technology to coun t and size paint overspray particles existed for many years prior to the establishment of Method 319. The commenter argued that the regulation of chromate-based paints should have been deve loped with the use of paint overspray as challenge particulates but the commenter blamed unspeci fied internal and external politics for this oversight.

The commenter argued that a dangerous gap exists between Met hod 319 certified filters and their real world performance in filtering out chromate paint particles from facility exhaust systems, and that the inflated filter efficiency data generated by Method 319 provides a false sense of confidence in the filtration market. The commenter argue d that neighborhoods in the vicinity of industrial complexes that exhaust chromate-based paints m ay be subjected to increased risks of cancer-causing agents, and recommended that the regulations on paint filter exhaust systems be updated to require the use of paint particle technology in deter mining the true efficiencies of filtration systems.

Response: The EPA did not propose any changes to EPA Method 319 in t his rule making, so this comment is outside the scope of this rulemaking.